Certain tomatoes seem to be better for drying than others, the meatier the tomato the better, so Romas are an especially good variety.. Just quarter them or cut them into thin slices and lay them on a flat surface like a cookie sheet. Salt and pepper the pieces and place the tray in the sun. Long, hot, dry days are ideal and it usually only takes about two days to remove the water. If you don't have sustained sun, you can finish them off in your oven, set a low temperature.. Once dried, just place them in airtight bags and put them into your freezer. Another way of preserving dried tomatoes is to pack them in jars and pour olive oil over them.