Drizzle each slice of bread evenly with 1 tablespoons olive oil. When the grill is ready, grill the slices of bread on both sides until evenly browned and charred in a few spots, about 1 minute per side.
Remove the bread to a plate and rub each piece with the garlic clove. Rub the cut side of the tomato on the slices of bread being sure to squeeze out some of the juice and pulp as you do. Use 1 tomato half for every 2 slices of bread. Drizzle each slice with an additional 1 tablespoon of olive oil. Sprinkle evenly with the salt and coriander seeds. Cut in half and serve warm.