Preheat the oven to 325 degrees F. Lightly brush 30 cups of mini-muffin pans with melted butter. Fill the unused cups halfway up with water.
In a medium bowl, combine the cookie crumbs, melted butter, and sugar. Press about 1 tablespoon of the cookie mixture into each mini-muffin cup, making sure there are no cracks. Bake for 8 to 10 minutes.
In a large bowl, whisk together the condensed milk, key lime juice, egg yolks, lime zest, vanilla extract and salt. Spoon 1 even tablespoon of filling into each warm crust. Bake the pies until the filling is set, about 12 minutes.
Transfer the muffin pans to a cooling rack and let stand for 20 minutes at room temperature. Use a small offset spatula or butter knife to carefully unmold the pies from the pans. When the pies are completely cool, top each with a dollop of whipped cream and decorate with a milk chocolate curl. Store untopped pies, wrapped or in an airtight container, in the refrigerator.
In a medium bowl whip the cream and sugar together until soft peaks form.