How to Make It
Heat oven to 450° F with the racks in the upper and lower thirds.
Brush 2 rimmed baking sheets with the oil and place 2 flat breads on each. Top with the marinara sauce, mozzarella, salami, and bell pepper, dividing evenly. Season with ¼ teaspoon each salt and black pepper.
Bake the pizzas, rotating the sheets halfway through, until the cheese is melted and the flat breads are golden, 8 to 10 minutes. Top with the arugula, if desired.