Approaching guys at work

So there's this really cute guy that works at the local Walmart and I'm really not sure how to go about asking him out. Back when he used to work the cash registers, I would try to pick his line and we made casual conversation here and there. We had a bit of a discussion about his watch once. Another time I had bought a bowl with no barcode on it. So we had a bit of a laugh as we realized the dilemma. Eventually, he just asked me if I remembered the price (it was cheap, like $1.50) and he just took my word for it without checking. I thought it was cute, after looking at the receipt, that he had manually entered the item name as "bowlllll" with a bunch of L's at the end haha.

Anyway, I have seen him in the store since, as recent as tonight. However, he hasn't worked the register in quite a while (at least not while I'm there, but I do have his work schedule pretty down-pat). So it's even harder for me to make any conversation with him What advice can you guys offer me to talk to him more and eventually ask him out?

I'm still pretty introverted and closeted; and I'm most definitely not the "stereotypical gay guy." But I'm coming around. The way I look at it is that I don't know this boy, worst thing that'll happen is that he says no. It's not like Walmart is gonna kick me out for asking him out or anything; and even if they did, there's a million and one other Walmarts out there.

My main thing is, how do I go up to him, what do I say? I mean, I kinda have a hunch that he may be gay or at least bi, but my gaydar has failed me so many times, I'd probably have more luck traveling cross-country in a Jaguar without breaking down.

And then there's the whole issue of putting him in an awkward situation at work. I mean, I know Walmart isn't exactly a "professional" atmosphere like where I work (I'm just out of school), but it's still a sticky situation nonetheless.