Heat oven to 400°F. Spray 2 cookie sheets with cooking spray.
Unroll pizza dough; cut into 6 squares. Place on cookie sheets. Spread pie filling evenly over dough.
In medium bowl, mix flour, brown sugar, oats and cinnamon. Cut in butter, using pastry blender or 2 forks, until mixture looks like fine crumbs. Sprinkle topping evenly over pie filling.
Bake 9 to 11 minutes or until edges are lightly browned. Cool 15 minutes.
Meanwhile, in small bowl, mix powdered sugar, milk and vanilla until smooth. Using fork, drizzle icing over flatbread.