Preheat oven to 350. Prepare a 10" tart pan with cooking spray; set aside. To prepare crust, combine cookies, granulated sugar, walnuts, and margarine. Mix well. Reserve three tablespoons mixture for topping. Press remaining mixture onto bottom and up sides of prepared pan. Bake for 12 minutes. Cool and set aside. Meanwhile, to prepare filling combine powdered sugar, cream cheese, pumpkin, cinnamon, nutmeg, ginger, and vanilla extract. Mix until smooth. Fold in whipped topping. Spread over baked crust. Sprinkle with reserved crumb mixture. Refrigerate three hours before serving.