Ladies, I need your advice?

So I think this girl at my workplace likes me. It all started in December when I first started to work there, me, her and 3 of our co-workers went to the movies(4 girls and me =) lol). I was only working there for a month and the girl bought my movie ticket.(After she did that, me and one of our friends looked at each other like huh?) After that, we didn't really have a lot of shifts together but when we did, she kinda looked at me with a glow. Anyway, recently, she started to tap my a.s.s. At first, I didn't want to tap her a.s.s because I always think some random **** would happen to get me in serious sht but then I just went for it. She laughed and went away on break. I have a feeling that she's flirting with me and with that feeling, I'm flirting with her as well. On several occasions, she put a hand print on my a.s.s as a joke and I'd do the same to her lol. So my question is what move should I make after this and, by her flirting with me, does she like me? And tomorrow I finish my shift when she starts her shift, I was thinking that I should say Hi n Bye and then tap her a.s.s as I'm leaving =D. I'm starting to like her as well. Ladies, your input would most appreciated, thanks.