Roll dough on a lightly floured surface into a 16x12-inch rectangle, stopping occasionally to let dough rest. Transfer dough to a greased 15x10x1-inch baking pan. Prick dough generously with a fork. Let stand for 5 minutes. Bake in a 425 degree F oven about 10 minutes or until light brown.
Meanwhile, cook onion, garlic, basil, oregano, and fennel seed in hot oil in a large skillet over medium heat about 20 minutes or until onion is tender, stirring frequently. Stir in chopped tomatoes and vinegar. Cook, uncovered, for 10 minutes more, stirring frequently. Spread tomato mixture over crust. Sprinkle mozzarella cheese. Arrange sweet pepper strips on top of cheese. Sprinkle with olives.
Bake for 12 to 15 minutes more or until cheese melts and pizza is heated through. Makes 20 appetizer servings.