Process flour and next 4 ingredients in a food processor until finely ground. Press mixture into a greased aluminum foil-lined 13- x 9-inch pan.
Bake at 350° for 20 minutes or until golden. Cool on a wire rack.
Heat 3/4 cup sugar and 1/2 cup lime juice over low heat, stirring until sugar dissolves. Remove from heat, and set aside.
Sprinkle gelatin over 2 tablespoons lime juice in a medium bowl; stir gelatin mixture, and let stand 3 to 5 minutes.
Add hot mixture, stirring until gelatin dissolves. Whisk in sweetened condensed milk and grated lime rind.
Place bowl in a larger bowl filled with ice; whisk mixture 10 minutes or until partially set.
Fold in whipped cream. Pour evenly over prepared crust; cover and chill 8 hours. Cut into diamond shapes. Garnish, if desired.