Toast the bread under a preheated grill or in a griddle pan until just starting to crisp and turn golden. Rub all over 1 side of each with the cut faces of the garlic.
Rub the tomatoes over the toast, using the cut faces and making sure the tomato juices soak into the bread. Drizzle with the oil, then sprinkle over the salt flakes.
Top with capers, olives or slices of Serrano ham before serving, if liked.