This achievement is actually deceptively simple. All you have to do is match up with a buddy and have your friend quit. The game treats it as if you wiped that person out, thus awarding you the full 500 points and crediting your foe with 0. Do this twice, achievement unlocked.
We tried this in one v.one matches, but it's reasonable to think that if you had a larger group everyone would have the benefit of the points.
So yeah, start two matches, your opponent quits, 1000 points and an achievement to you. Just remember to repay the favor. ;)
To be fair, we didn't try this right at the beginning of our session. We had put in two or three matches, but I was on the losing end of all but one and then got it after two quit outs. If someone with no progress wants to confirm it works, please do. ;)