How can a straight-like gay approach a guy?

I'm discreet. I always see this guy, for 2 weeks now, same time, same place - lunch time in a coffee shop.. I really like him. I don't know anything about him except for the company where he works. I can't even see his name on his ID. For the past week, I was able to "magnet" his eyes and look into mine, but that's about a split second I think, though it has happened several times. He's always with his friends and I can't approach him. I can't because I'm "straight" (hehe) and I might offend him/his friends and might be surprised what I'm after. I just really want to know him. What's the best thing I can do?