I believe that the best would be if you just approached him and started a small talk. Do that often and see what happens! Don’t waste time wondering how he feels about you but take some action! Good luck!
I’m not a big fan on dating in the work place. I’ve done that before, and when things didn’t work out it was very uncomfortable. On the other hand I know a couple who met at work and are now married (working two separate jobs). You have to make your feelings known, anything is possible.