Preheat oven to 375. Prepare 9" pie pan with cooking spray. In a small bowl, combine sugar and cinnamon; sprinkle two tablespoons of the mixture over prepared pan. Sprinkle three tablespoons walnuts over sugar mixture. Place roll pieces evenly over walnuts; sprinkle with remaining sugar mixture. Dot with margarine. Bake for 20 minutes, or until golden brown. Drizzle icing from rolls over top. Then, sprinkle with remaining walnuts. Serve warm and cut into wedges.