I think the most important question is do you like him? If you do, and he is being friendly and flirty you don't risk too much by asking him to hang out. Just find a way for you guys to spend some time outside of work. Invite him to a party if that's more comfortable. I think that's an easy generally safe way to nudge at him to make a move or an opportunity to charm him on the event =)
In my experience, a guy who's grabbing your waist or touching your hand is into you. If you really want to be sure, ask him out for drinks after work sometime. It's innocent enough, but then you can get a real feel for him outside the work-place.
i think he's into you if he's touching you alot like that
just ask if he wants to go for a drink after work. then when it's just the two of you you'll be able to judge him better with no other distractions. or he may just come out and say that he's into you. good luck!
You won't ever really know for sure unless you are straightforward. If he hasn't made a move by now I would say just straight up ask him. There was a guy who I knew through my job who I was convinced liked me but was too shy to do anything about it. He'd seek me out at functions and was emailing me all the time but when I finally told him he should give me a call sometime and gave him my number, I stopped hearing from him as much and now we only do the "Hey, how are you?" routine. He's currently back together with his ex wife. Apparently it was a "he's not that into you" situation. I'm not a believer in beating around the bush or playing games so if you like him, take a breath and ask him to hang out. I'm glad I did what I did b/c I was proud I took the bull by the horns and glad I found out early enough that it was just not happenin'.