Cool Lime Pie

1 pkg. (4 serving) vanilla pudding (reg)
1 pkg. (4 serving) lime jello
2 c. water
1/4 c. sugar (optional)
1 1/2 t. grated lime rind
2 T lime juice
3 1/2 c. cool whip
1 choc pie crust

Combine pie mix, gelatin, sugar, and water in saucepan. cook and stir over medium heat until full boil Add lime rind and juice. Pour into bowl, cover with plastic and chill until slightly thickened. Fold in 2/1/2 c. of the topping. Spoon into crust. Freeze 1 hr. or chill 3 hrs. Garnish with remaining topping and lime slices if desired.