Make the crust: Crush cookies until fine in a food processor. (You can also place the cookies in a zip-top bag and use a rolling pin or mortar and pestle to crush them.) Combine crushed cookies and softened butter in a medium bowl. Stir until well combined. Press onto the bottom and up the sides of a 9-inch round pan or pie plate. Freeze for at least 30 minutes.
Make the salted caramel: place all ingredients, except salt, in a heavy-bottomed saucepan. Bring to a boil, stirring occasionally, for 10 minutes. Remove from heat; stir in salt. Pour into prepared crust; refrigerate for 2 hours or until caramel is cold.
Make the whipped cream topping: In the bowl of an electric mixer fitted with the whisk attachment, whip cream on medium-high speed until slightly thickened; about 2 minutes. Add vanilla, then gradually add confectioners' sugar, whipping until soft peaks form. Set aside.
Remove pie from the refrigerator. Top the caramel layer with sliced bananas. Place whipped cream on top, creating peaks using an offset spatula. Chill for at least 6 to 8 hours or overnight. If desired, dust top with ground cinnamon before serving.