Vanquish heats up fat without disturbing the skin and some of the fat dies.
Vanquish avoids the skin which is why it is noninvasive, no need to worry about scarring. However, it will also not tighten skin. If your fat is gone, you need to consider other ways to try to tighten the skin.
Congratulations on your massive weight loss. I would suggest an evaluation by a plastic surgeon for skin removal. Over time the skin will remodel and tighten but probably not as much as you would like. Exilis has an abdominal applicator and can be used to heat up the skin superficially to tighten the skin as well.