For a guy in your situation (if what you're saying here is true and not just some delusional perception), I will guarantee this will work for you with little to no awkwardness involved:
Before she comes over, literally tell her (don't ask) that you are going to kiss her when she comes over because you want to break that tension/awkwardness that has been there.
She will know exactly what you're talking about and will most likely respond with an enthusiastic "OK!!!" From that point on its a slam dunk. There is literally no wrong way to go about doing it. The only way you can mess it up is simply not doing it at all.
However, even though women are OK with knowing that you're going to kiss them, most don't want to know the finer details in exactly how and at what moment it's going to happen. They still like the surprise of it. So don't talk about it, even if she's curious and asks. Keep that part a mystery to her. Let her imagine all of the different scenarios on how its going to play out (because she most definitely will), all the way up to the point it actually happens.
My suggestion: Don't do it when she walks through the door. That will be one of the scenarios she will expect. Another scenario she will imagine is after you two are settled in and chatting on the couch or whatever.
Like I said, no matter what you do, anything you do will still work. You're not going to fail. But if you want to make the biggest impact and maximize this experience for her (which is good for you), it's best to pick an unexpected moment that she isn't going to imagine.
That moment is when she is in the middle of doing something and you stop her to pull her in for the kiss.
Here's just one example of how you can do it:
When she arrives, let her throw her stuff down and ask her to follow you into the kitchen to help you grab some drinks, snacks, whatever. Go to the fridge to grab drinks, open the fridge door and then and ask her to grab a few glasses out of the cabinet for you. As she's reaching (preferably facing away from you), walk up to her, take the glasses out of her hand as she turns, put them on the counter, grab her waste, pull her into you and give her every ounce of cool, calm, collective confidence you can muster up in your eyes and body motion as you go in for the kiss.
Keep a nice, confident pace in doing it. Not so fast that you startle her and not too slow like it's some cheesy romantic movie. Just giver her a few brief seconds, just enough time for her brain to think, "OMG! It's Happening right now!".
Even a virgin will be puddy in your hands from that point on. Just don't wait too long to kiss her again after that. You want to keep the physical stuff going, even if it's a casual peck on the lips here and there. Anything. Because that tension is going to come back if you chat her up for 2-3 hours without making another move.