1. Heat a large pan or grill pan over medium-high heat. Spray pan with cooking spray.
2. Combine the next four ingredients in a bowl and add salt and pepper to taste. Using your hands, toss everything together so that the peppers and beans are evenly coated in the marinade. Remove just the peppers, reserving the beans and the marinade and place them on the hot pan. Cook, about 8 minutes a side until they're tender. Remove from pan to cool.
3. Meanwhile, slice the ciabatta loaf in half horizontally, and then vertically into 4 equal top/bottom pieces. Hollow out the bread on the bottom of each of the sections to create a little divit. Fill the hollowed out areas of each of the bottom loaf pieces with 1/4 cup of marinated beans. Reserve remaining vinegar mixture. Finish each sandwich by layering on the basil, the cooled pepper, the arugula and 1/4 of the sliced mozzarella. Drizzle the remaining vinegar mixture over each sandwich and season again with salt and pepper to taste. Cover with top piece of bread.