Put a pizza stone on the lowest rack of the oven. Preheat to 400'F. (If you use a metal pan instead, do not preheat the pan.) Toss the vegetables with oil and vinegar. Cover 2 dozen inch pizza shells with the cheese (leaving a 1 cm rim); sprinkle the vegetable mixture over the cheese. Slide the pizzas onto the pizza stone. Bake for 15 minutes, or until the crust is golden brown. MAKES 2 MEDIUM PIZZAS, 8 SLICES EACH. Per slice: 177 calories, 21 grams carbohydrates, 6 grams protein, 1 gram fiber, 7.6 grams fat (2 grams saturated) 268 milligrams sodium.