Painting these plastic cabinents is a difficult task since they were designed to repel most substances in order to get good washability. You first must make sure the surface is Clean and Dry - this means that there should be no oils or splattered food left on them. I would probably not sand the surface since this will just place more scratch marks on the surface which will show after painting has been applied. Use of a very good bonding primer would then be used to ensure proper adhesion to the plastic. Kilz would not be an appropiate primer since this is more of a everything primer. I would get a Sherwin-Williams product called Bonding primer. This can then be followed by either an oil or latex topcoat. Oil base would spread easier and probably provide a better overall look.