In gallon-size food-storage plastic bag, shake remaining sugar and the orange peel until well blended. Add rhubarb; shake until well coated. Arrange rhubarb in a single layer, down centre of dough, to within 1 inch of edges. Sprinkle rhubarb with remaining orange sugar. Fold dough edges over rhubarb. Sprinkle dough edges with cinnamon sugar.