Preheat oven to 375°F. Melt butter in a small saucepan. Stir in sugar. Add finely crushed graham crackers; mix well. Spread evenly into a 9-inch pie pan. Press onto the bottom and up the side to form an even crust. Bake for 4 to 5 minutes or until the edge is lightly browned. Cool on a wire rack before filling.
Combine juice and cornstarch in a small saucepan; cook and stir until thick and bubbly. Cook and stir for 2 minutes more. Transfer to a large bowl. Cover the surface with plastic wrap; cool for 30 minutes. Divide the mixture into 3 small bowls.
Fold each type of fruit (mango, papaya, and kiwi) into one of the bowls of the fruit juice mixture. Spoon the fruit into the pie shell, arranging it as desired; press the fruit down lightly with a rubber spatula or the back of a large spoon. Cover with plastic wrap or foil and chill for 3 to 4 hours. Serve with whipped dessert topping, if desired.
Tip: For easier cutting and better flavor when using a purchased pie shell, preheat oven to 375°F. Brush the pie shell with a lightly beaten egg white and bake for 5 minutes. Cool on a wire rack before filling.