Take a deep breath, walk up to them, say "hi, I like you, would you like to go out sometime?" and accept whatever they say. If you get it out there (and yes, I know it's really, really impossibly hard), the worst that can happen is they'll say "no", and the best that can happen is they'll say "yes, let's do this thing" and go out with you. If you don't? You'll wonder "what if" for a long, long time.
