Combine first 8 ingredients in a medium bowl; chill.
Flatten each bread slice with a spatula or rolling pin. Combine garlic and butter in a small bowl, and spread evenly over each side of bread slices.
Heat a large skillet over medium-high heat. Add flattened bread, in batches. Top with a smaller skillet or press down with a spatula to flatten bread a little more; cook 2 minutes on each side or until golden brown. Repeat procedure with remaining flattened bread slices. Spoon tomato mixture evenly over each bread slice. Sprinkle with cilantro. Serve immediately.