Is this person gay? I can't quite tell.?

Just say "Yo personal space" or something like that, or "hey, do you realize you're a little handsy, I'm not big on the touching". Simple, to the point, and non-offensive...if his feelings are hurt from asking him to stop touching you, in a tactful way, then that's his choice to have his feelings hurt...think about your feelings, if you don't want to be touched, you shouldn't have to be.