Heat oven to 350°F In food processor bowl with metal blade, place pretzels and sugar. Cover; process 15 to 20 seconds or until finely crushed. With food processor running, drizzle melted butter through feed tube, pulsing to mix well.
Press crust mixture in bottom of ungreased 11x7-inch pan or glass baking dish. Bake 5 to 8 minutes or until set and golden brown. Cool completely, about 45 minutes.
In large bowl, beat cream cheese and dry pudding mix with electric mixer on medium speed until fluffy. Add lemonade concentrate and food color. Beat on low speed until mixed. Beat on medium speed until fluffy. Fold in 2 cups of the whipped topping. Spread over crust. Spread remaining whipped topping over lemonade mixture. Refrigerate at least 2 hours or until set.
Cut dessert into squares. Garnish each serving with lemon.