HEAT oven to 350°F. Line 24 muffin cups with paper baking cups.
BEAT cake mix, water, oil and egg whites in large bowl with electric mixer on low speed until moistened. Beat 2 minutes on medium speed or until blended. Divide evenly into prepared baking cups.
BAKE 18 to 20 minutes or until toothpick inserted in center comes out clean. Cool 5 minutes. Remove from pans. Cool completely on wire rack. Remove paper baking cups. Cut cupcakes in half horizontally.
COMBINE frosting and topping in large bowl until blended. Chill 15 minutes. Place about one fourth frosting at a time into corner of 1-quart size resealable plastic bag. Cut medium-size corner off bag. Squeeze frosting over bottom halves of 6 cupcakes. Place tops on cupcake. Squeeze frosting in a circular pattern on top of cupcakes, beginning at outside edge and working to center.
REPEAT with remaining cupcakes, 6 at a time. Garnish with pieces of orange peel. Chill until ready to serve.