If roasting your own bell peppers, slice into fourths, place on a cookie sheet, drizzle with 2 teaspoons extra virgin olive oil and roast for 20 minutes. Allow to cool slightly before removing peeling. Roasted peppers can be purchased at your local grocery.
In a small skillet, add 1 tablespoon oil, heat to medium-low and sauté mushrooms until soft, about 8 minutes.
While mushrooms sauté, place bread cut side up on a cookie sheet, toast until lightly golden. Remove toast, add 1 tablespoon mozzarella, continue toasting until cheese melts. Remove bread from oven and top with pesto, mushrooms, bell peppers, tomatoes and arugula.