Bring a medium-size saucepan of water to a boil. Cut a cross at the root end of the tomatoes and drop them into the boiling water. Cook until the skin of the tomatoes begins to split, 1 to 2 minutes. Transfer the tomatoes to a bowl of iced water. Peel and seed the tomatoes, then roughly chop them. Place the tomatoes in a strainer and put strainer over a bowl for 20 to 30 minutes, to allow tomatoes to release all juices.
Brush the bread lightly with olive oil and place over a hot grill or under a broiler until golden on both sides.
Put the tomatoes, garlic, capers, oregano or basil in a medium-size bowl. Season with salt and several grindings of pepper. Add the oil and mix everything well. Spoon the tomato mixture over each bread slice, arrange on a large platter, and serve.