Stir together tomatoes, olives, red onion, anchovy, (if desired), poblano chile pepper, vinegar, and garlic in a medium bowl. Let mixture stand at room temperature for 20 to 30 minutes.
Bias slice the bread into ½ inch slices. And place slices on a baking sheet. Bake for about 5 minutes, or until light brown in a 350 degrees F oven. Turn bread over and bake for 5 more minutes.
Arrange mozzarella cheese slices on the warm toasted bread. Drain tomatoes and top the bread slices with the tomato mixture. Bake about 5 minutes more. Cheese should be melted, and tomato mixture should be heated through.