Description

• Preheat oven to 350.
• Whisk oil and vinegar in a bowl together with salt and pepper, and marinate onion slices and tomatoes in it for about 10 minutes.
• Meanwhile, rub cut side of garlic onto bread and toast bread slices. Set aside.
• Remove tomatoes and onions from marinade and put into a larger bowl, reserving marinade. Combine tuna, capers, and spinach with tomatoes and onions.
• Divide tuna mixture among 4 slices of bread. Drizzle with a bit of the reserved marinade and top with remaining bread slices.