Heat oven to 350°F. Place coconut in single layer in 13 x 9-inch baking pan. Bake 18 to 20 minutes or until coconut is lightly toasted, stirring after 12 minutes. Cool completely; set aside. For crust, beat margarine and sugar in large bowl until creamy. Add combined oats, flour, nuts, cinnamon and baking soda; mix well. Reserve 1 cup coconut for topping. Stir remaining coconut into crust mixture. Press dough evenly onto bottom of ungreased 13 x 9-inch baking pan. Bake 18 to 20 minutes or until golden brown. Cool completely on wire rack. For filling, combine all ingredients in large bowl. Spread mixture evenly over cooled crust. Sprinkle with reserved coconut, pressing lightly. Cover and refrigerate 3 hours or as long as overnight. Cut into squares; garnish with lemon twists, if desired. Store covered in refrigerator.