Finely chop the chocolate then melt in a large microwave safe bowl by microwaving in thirty second intervals, stirring thoroughly after each interval. When melted, stir in the sweetened condensed milk and set aside to cool.
Finely crush 12 graham cracker sheets. Add the salt. Melt the butter and stir it in to create a graham cracker crust mixture. Divide the crust mixture between eight cups. Press down.
Gently fold two thirds of the container of Cool Whip into the chocolate mixture, taking care not to mix too vigorously. Fold gently until completely incorporated. Be sure to reserve one third of the container for topping the pie cups later.
Divide the chocolate mixture between the eight cups.
Place all the cups in a 9x13 baking dish, cover the entire thing with plastic wrap, and refrigerate for at least one hour.
Before serving, top each cup with a dollop of the remaining Cool Whip and garnish with berries if desired.