I have access to his number, should I use it?! I like him!?

I like this guy at my work, and he's always using the intercom to call my checkstand and hang-up as a little joke. He did it every time he didn't have a customer. So I knew he was thinking about me? Then he asked to get off the register and bag instead. And when he did, he came straight to mine to help me, even though I didn't have a customer. Yesterday he wanted to know what I was doing and I didn't say anything, but he made the inferance that I was going on a date. Instead of saying he was wrong I said nothing. So today he kept bugging me and asking me what I did, and who the date was with. He told my friend I seemed emabressed when asked if I was going on a date and then kept asking my friend what I was doing. Well, my otherrr friend Emily, said she has his number...and since I'm not able to pull out my phone on the job I never casually ask for his...should I take the number from her and then prank call him as a joke...then tell him it was me? Do you think me might like me?!