For lukewarm bread with peppers and mozzarella, first cut the peppers into eighths and remove the seeds. Grill skin side up under the oven broiler for 10-12 minutes until the skin blisters black. Remove, cover with a wet dish towel and let cool for 10 minutes. Then peel off the skin.
While the peppers are in the oven, prepare the sandwiches. Brush each slice with a little olive oil and rub with a garlic clove cut in half. Once the bell pepper is done, place in the oven for 3-5 minutes until crispy.
Remove the bread slices and top alternately with peppers and mozzarella that has been pulled apart. Add salt and pepper and serve the lukewarm bread with peppers and mozzarella garnished with arugula.