Preheat the broiler. Arrange crackers in a shallow baking pan lightly sprayed with nonstick cooking spray or lightly greased with shortening. Cut cheese slice in half lengthwise and into sixths crosswise, making 12 squares.
Place a piece of cheese on each cracker. Spoon about 1 teaspoon pizza sauce atop. Top with olive, if desired. Broil 5 to 6 inches from the heat for 1 to 2 minutes or until cheese is melted. Makes 3 or 4 snack servings.