Laser assisted liposuction might tighten the skin a little. However, if the amount of excess skin significant, only excision will give you a good result. Unfortunately there will be a scar across the lower abdomen. You'll have to decide if it's acceptable or not.
SmartLipo can shrink the skin better than traditional liposuction. If your skin doesn't shrink sufficiently after liposuction then you can be left with "flabby skin" which is also not desirable. If you have a consultation with a plastic surgeon that performs both tummy tucks and SmartLipo then he or she can give you a very credibel opinion on which would be better for you.