To paint over ANY surface, without sanding, use a product called 'ESP Easy Surface Prep', available at hardware and paint shops. Wipe on, wipe off and paint in 90 minutes. Works well over enamel paint , without having to sand. SAVES HOURS of work. It was recommended to me by a professional painter.
Keep crumbs out with plastic tubing: If crumbs, papers or even flatware falls into the gap between your countertop and refrigerator, fill the void with nearly invisible plastic tubing. Clear tubing is available at home centers in several widths starting at 1/8 in.