Heat oven to 400F. Heat large nonstick skillet over medium heat until hot. Add ground beef and bell pepper; cook 8 to 10 minutes, breaking into 3/4-inch crumbles and stirring occasionally. Pour off drippings. Stir in tomatoes and oregano; continue cooking 5 to 7 minutes or until liquid has evaporated. Remove from heat; stir in cheese. Set aside.
Sprinkle cornmeal evenly over rimmed baking sheet. Unroll pizza dough lengthwise on baking sheet, straightening edges of dough if necessary. Spoon beef filling over long half of dough, leaving 1-inch border on 3 sides. Gently lift and pull top half of dough over filling to enclose; pinch dough edges to seal.
Bake in 400F oven 15 to 20 minutes or until crust is golden brown. Cool 5 minutes. Cut crosswise into 8 slices.
Cook's Tip: Cooking times are for fresh or thoroughly thawed ground beef. Ground beef should be cooked to an internal temperature of 160F. Color is not a reliable indicator of ground beef doneness. For easy cleanup, line baking sheet with parchment paper. Sprinkle with cornmeal and proceed as directed above.