Preheat the oven to 400°F.
Cut the bagels lengthwise, Place on a baking sheet.
Spread 1 Tablespoon of the tomato paste on each bagel half. Sprinkle 1/2 cup mozzarella cheese over the tomato paste, and top with 5 pepperoni slices.
Place in the preheated oven for 10 minutes, or until the cheese is melted.