Throughout Italy and especially in Tuscany, little open-faced sandwiches (crostini) are popular as a café snack. Fresh mozzarella cheese can be found in the deli section of most grocery stores. It can be vacuum-sealed or packed in a liquid brine.
16 (1/2-inch-thick) slices Italian or French bread baguette
Coat bread slices with cooking spray; place on a baking sheet. Bake at 400° for 5 minutes or until lightly toasted; set aside.
While bread bakes, heat oil in a large nonstick skillet over medium-high heat. Add garlic; sauté 1 minute or until lightly browned. Add spinach, pepper, and salt, and sauté 30 seconds or until spinach wilts. Place spinach mixture in a bowl. Chill 5 minutes to quickly cool. Stir in tomato and vinegar. Top each bread slice evenly with cheese and about 2 tablespoons spinach mixture. Serve immediately.