Yeah, Just ask her out. I wouldn't phrase it as a "date" though, I never liked that, it makes assumptions, to me a "date" gives away too much, its obvious what you're up to. I mean, if you say "wanna hang out on friday" vs "wanna go on a date on friday", the hang out version there's no expectations in that language on her part that you're trying to get with her, which in my experience is a plus, she'll be wondering "does he just want to be friends or does he want something more", which seems to be an advantage especially if she already digs you (which she seems to, a little bit of hard to get goes a long way, dont overdo it though)... anyways that's just my view on it and I'm starting to ramble...

Ask her what if wants to do something on insertdayoftheweekhere-day, have an idea of what to do, "wanna go play pool/go see a movie/ make sweet love under the starlight" Ok, the last one was a joke, but you get the idea.