Heat oven to 350°F (176°C). Place a 9-inch round tart pan on a rimmed baking sheet.
Finely grind cookies with sugar and salt in a food processor. Add melted butter and process until clumpy.
Press crumb mixture firmly into bottom and up sides of pan. Bake until crust is lightly browned, about 10 minutes. Let cool completely.
In a large bowl, beat the cream cheese, butter, sugar, peanut butter, salt and vanilla together until fluffy.
Scrape the mixture into the tart shell and smooth the surface with a spatula. Chill while preparing the topping.
Heat chocolate, pinch of salt and cream together until the chips are mostly melted. Stir until smooth.
Let sit for 5 minutes to cool slightly then pour over peanut butter filling and gently spread smooth.
Sprinkle with flaky salt, if desired. Chill the tart until firm.
Serve in wedges.
