1.
Leonard Snart is the kind of guy who pays an almost insane amount of attention to details - it's what has kept him well above the herd of petty thieves and out of prison for a long time.

That is why taking apart his Cold Gun is almost a physical pleasure: a myriad of minuscule pieces artfully disposed, almost woven in a seamless construct, a web of fine cables oh so easy to disrupt, the space used with brilliant economy to minimize the volume…
He likes to think – and he's probably right – that he can almost see the exact steps that whoever invented this marvelous toy has taken to build it: the enthusiastic rush when the core first came together, the frustration when the cool but impractical first concept for the outer case just wouldn't get along with the internal components, and the final, painstakingly meticulous last tweaks and touches that made it perfect (though he suspects that it's still a prototype, judging from a couple of spots not as refined as the rest).

Snart respects genius when he sees it and his gun is practically made of genius, so when he turns around and sees that said genius belongs to a trembling half-pint of a kid (seriously, what's with the age average of the Flash and his associates?) threatening him with what's obviously a rather fancy vacuum cleaner, the temptation to just laugh is so strong that he almost forgets where he is and what he is doing.
Almost.
He doesn't, naturally, and manages to walk away victorious from a direct confrontation with The Flash. The adrenaline, the possibilities, the new-found challenge, it all gives a spring to his step that is almost a skip as he walks away and when he's finally at a safe distance he lets that previously bottled up laughter bubble to his lips like he hasn't done in years.

Snart is a man of details.
The fact that by the next two weeks he knows more about Cisco Ramon than what will probably ever be useful in any kind of plan (unless the plan is to poison the chips that he now knows Cisco always orders with his beer) is all about being thorough about researching the Flash's Team, and has nothing to do with the fact that the juxtaposition of Cisco's impressive brain and his less than matching looks actually made the word "cute" - a word Snart hasn't used since he was seven – pop spontaneously in his head.

2.
Leonard Snart is the kind of guy who is driven mostly by logic, and that is also a quality that keeps him from making stupid mistakes in a moment of panic or cockiness – Mick does that more than enough for both of them.

So yeah, he acknowledges that maybe if the circumstances were a little (as in completely) different, he would have probably at least tried to get Cisco in a situation that involved himself and a distinct absence of clothes, but the circumstances being what they are he doesn't even consider acting on the silly thought.
But just because he can keep it at bay without too much effort (because really, you don't become one of the best in his profession if you don't get your priorities straight and avoid being led around by your dick), it doesn't mean that said silly thought is completely erased.

And that is what had lead to the creation of a quiet, secluded corner of Snart's mind dedicated to filing Cisco-related things that Snart just… keeps. There. Surely not to be examined in a second moment.
Things like how he thought that there was really no need for Lisa to kiss the engineer, and how really inappropriate it was and how he really wish she hadn't done that. Because there was no need. Stupid baby sister.
Or how on the other hand there was no real need to have Cisco get closer just to tell him he had noticed the tampering with the firing pin, but he does it anyway because he wants an excuse to revel in that stark height difference they have - wearing just a well-worn T-shirt the guy looks tiny beside him.
(That particular observation threatens to send him down a spiral of vivid fantasies involving a table, power games and lots of biting, so Snarts shuts it down really fast.)

Snart is good at controlling himself so it never gets past the random, sudden, passing thought.
But he looks at Cisco and sometime sees (details, details) reactions and glances and a catch of breath that doesn't look completely fear-induced.
So maybe he jumps in a little too fast to stop Mick from beating him senseless.
So maybe he gets a little closer than what is strictly necessary when he shoves the engineer and his brother out of the house.
So maybe he readily agrees with the Flash not to hurt his "friends and family" because he had already decided to avoid it when possible, and not just because of his ego inflating at being recognized as "good" by the speedster (but is that too).

Because the thing is – and that is where it kinda stings - Snart is fairly sure that in the previously mentioned completely-different-circumstances scenario that will never be, he would have a decent chance of succeeding.
And if that makes Snart want to keep Cisco around and alive, with his beautiful brain, the nerdy T-shirts and the lame nicknames that are a big part of what makes his game with the Flash so fun, well… that's a small detail that is no one's business.