Arrange 19-20 whole gingersnaps over bottom and sides of the pie plate. Crush remaining gingersnaps. Combine pumpkin with sugar, salt and spices; mix well. Stir in pecans. Chill.
Fold the chilled mixture into the softened ice cream and spoon into the cookie "shell". Sprinkle gingersnap crumbs over the top of the pie and freeze, well covered.