Prepare Graham Cracker Crust. Cover and chill about 1 hour or until firm.
For filling, in a medium bowl combine sweetened condensed milk, the 1 teaspoon lime peel, and the lime juice. In another medium bowl beat 1 cup of the cream with an electric mixer on medium speed until soft peaks form (tips curl). Fold whipped cream into lime mixture. Spoon filling evenly into crust-lined pie plate. Cover and freeze for 2 to 4 hours or until firm. Keep remaining cream chilled until ready to serve.
To serve, remove pie from freezer. In a medium bowl beat remaining 1 cup cream on medium speed until soft peaks form (tips curl). Spread whipped cream over filling. If desired, sprinkle with additional lime peel.
Graham Cracker Crust
In a medium bowl combine graham cracker crumbs and sugar. Drizzle with melted butter; toss gently to coat. Press mixture evenly onto bottom and up side of a 9-inch pie plate.