Here, mozzarella cheese and tomato slices are topped with crunchy breadcrumbs and drizzled with balsamic syrup for an elegant take on a classic summer appetizer. The balsamic syrup can be made several days ahead, or you can omit it to save time.
Preheat oven to 450°F. Spray baking sheet with cooking spray.
Heat vinegar in small saucepan over medium heat. Bring to a simmer and cook 10 minutes, or until syrup-like and reduced to 1/3 cup. Remove from heat, and set aside.
Lay 8 tomato slices on prepared baking sheet. Place 1 cheese slice on each tomato slice. Spread 1/2 tsp. pesto on each cheese slice, and top with remaining tomato slices.
Place bread in bowl of food processor, and pulse until chopped into fine crumbs. Pour into small bowl; toss with olive oil, and season with salt and pepper. Sprinkle crumbs on top of tomatoes, and bake 5 to 7 minutes, or until crumbs are golden and cheese is soft.
Toss corn and arugula together in bowl, and turn out onto serving platter. Place tomato stacks on top, and pass balsamic syrup for each guest to drizzle on top of tomatoes.