Most people hate to clean shrimp, but these days they're sold peeled and deveined. Or buy a pound of shrimp when you have some extra time, clean them and freeze in 1/4 pound portions to have on hand. It's less expensive that way!
Place tomato pieces in a bowl.
Pinch off delicate stems and leaves from bunch of watercress to measure 1/2 cup; reserve.
Heat 1 tablespoon oil in a nonstick skillet over high heat. Add shrimp; cook 4 minutes, stirring and shaking skillet. When cooked through, add to tomatoes.
Toss capers and lemon juice with tomatoes and shrimp. Season with salt and pepper to taste.
Brush one side of toast (crostini) with remaining teaspoon oil. Rub oiled side of toast with garlic, cut-side down, using both halves of garlic or to taste.
Place toast in the center of a large dinner plate. Spoon shrimp and tomatoes over toast. Top with watercress and serve immediately.
Serves one: 371 calories, 19 grams fat, 173 milligrams cholesterol.