Preheat the oven broiler on high. Set the oven rack in the middle of the oven.
Toss the tomato, garlic, and oil on a foil lined baking sheet. Season with salt. Place under the broiler until the garlic is golden brown and tomatoes are soft. (keep an eye on it so it get burnt). Place in a blender and pulse until smooth.
Turn down the broiler to low and move the rack toward the top of the oven. (make sure to use oven mitts for safety)
In a bowl, mix together the tomato and pesto sauce. Season with salt and pepper to taste, then spread on the inside of each bagel.
Top with mozzarella and pepperoni. Lay on a foiled-lined baking sheet and place under the broiler until melted and golden brown, rotating the pan every few minutes. (Keep a watchful eye while using the broiler.)