Preheat the oven to 400°F.
Brush one side of the bread slices with some of the olive oil and arrange on a baking sheet oiled side up.
Bake until lightly browned and crusty, about 4 minutes.
Spread the olivada or chopped olives on each toast, cover each with a slice of mozzarella and top with a slice of tomato.
Brush the tomatoes with the remaining oil and sprinkle with the salt and pepper. Bake until the cheese is melted, about 8 to 10 minutes.
Serve at once. * Olivada is a puree of black or green olives packed in oil that is sold at specialty food stores.
You can substitute tapenade or pesto for the olivada.