Position oven rack in center of oven. Preheat oven to 425F. In large skillet cook onion in 1 tablespoon of the olive oil over medium-high heat 3 to 5 minutes or until onion is just tender. Place bread shell on baking sheet; brush with remaining olive oil. Bake 5 minutes.
Meanwhile, stack beef slices on cutting board; slice into strips. Top shell with beef, sweet pepper, onion, cheese, and pizza seasoning. Change oven setting to broil. Broil pizza 4 to 5 minutes or until toppings are heated through and crust is browned. Cut in wedges. Serves 4.