Preheat oven to 350°. Fit piecrust into a 9-inch deep-dish pie plate according to package directions; fold edges under, and crimp.
Stir together crushed gingersnaps and next 3 ingredients. Press mixture on bottom and 1/2 inch up sides of piecrust.
Bake at 350° for 10 minutes. Let cool completely on a wire rack (about 30 minutes).
Stir together pumpkin and next 6 ingredients until well blended. Pour into prepared crust. Place pie on an aluminum foil-lined baking sheet.
Bake at 350° for 30 minutes. Sprinkle Pecan Streusel around edge of crust. Bake 40 to 45 minutes or until set, shielding edges with aluminum foil during last 25 to 30 minutes of baking, if necessary. Insert ginger cookies around edge of crust. Let cool completely on a wire rack (about 1 hour). Dollop with Ginger-Spice Topping; dust with cinnamon.