Place the ciabatta slices on a large baking tray and drizzle with olive oil. Cut the garlic cloves in half and rub the cut side on bread slices (discard garlic cloves after this).
In a bowl, mix the tomatoes with 1 tablespoon olive oil, olives and basil. Season with salt and pepper.
Grill the ciabatta until golden brown. Remove from the oven and top with the tomato mixture. Serve immediately.