Most Helpful Guy
Sounds like he does like you. Subtle flirting it seems to me, maybe he's not sure if you like him or not. He may also be trying to gauge your reactions and such. He also might be subtle because since the two of you work together and he may be unsure if you feel the same way, he might just not want to make the work enviroment awkward... try giving some more straight forward signals and see how he reacts.