Toast the bread slices on a grill, turning once, or in a toaster until golden brown.
Peel garlic, if using, and rub cloves on toast. Cut tomatoes in half crosswise and rub toast with cut side of tomatoes, squeezing gently so that each piece of toast is coated with juice, bits of tomato flesh, and seeds. Drizzle toast with olive oil and sprinkle with salt to taste.
Note: Nutritional analysis is per serving.