Preheat oven to 375°. Working with prepared dough, press down edges with floured fork tines, leaving 1-inch between crimping. Freeze 10 minutes or until firm.
Line bottom of dough with foil; top with pie weights. Bake in middle of oven 20 minutes or until set. Remove weights and foil, and return to oven. Bake 8-10 minutes more. Transfer to a wire rack; let cool.
Whisk together mashed sweet potato with whole eggs, 1 egg white, 1/2 cup maple syrup, ginger, nutmeg, and salt. Spoon into shell, and brush edges with remaining egg white; sprinkle with sugar. Bake in middle of oven 40 minutes or until set. (If crust is becoming too brown, cover with foil.) Transfer to a wire rack.
Spray a piece of foil with cooking spray. Toast pumpkinseeds in a skillet 1-2 minutes or until syrup has reduced and seeds are golden. Transfer to foil; spread in 1 layer. Let cool 15 minutes. Crumble, and garnish pie. Slice and serve.