Combine cookie crumbs and butter and press on bottom and up the sides of a greased 9" pie plate. Cover and chill.
Place cold water in heavy saucepan and sprinkle with gelatin. Let stand 1 minute
Add caramels, milk and salt. Cook and stir over low heat until gelatin is dissolved and caramels are melted. Refrigerate 1-2 hours or until mixture mounds when stirred with a spoon.
Stir in pecans and vanilla. Fold in cool whip and pour into crust. Chill 6 hours or overnight.
If desired, garnish with caramel ice cream topping and additional pecans.