Preheat oven to 425º.
Bake potatoes at 425º for 1 hour or until done; cool slightly.
Cut each potato in half lenghtwise, scoop out pulp, leaving a 1/4-inch-thick shell. Reserve potato pulp for another use. Place potato shells on baking sheet; spray inside of shells with cooking spray. Bake at 425º for 8 minutes or until crisp. Divide pepperoni and cheese evenly among potato shells. Bake at 425º for 5 minutes or until cheese melts. Top each shell with 1 tablespoon sour cream, 1 tablespoon onions, 2 teaspoons olives, and 1 1/2 teaspoons salsa.