Preheat the oven to 350 degrees F (175 degrees C). Press pie crust pastry into a pie dish.

Bake in the preheated oven until lightly golden, 10 to 12 minutes.

Arrange salmon into the baked pie crust to cover evenly. Spread cream cheese over over salmon layer using your hands. Sprinkle dill over cream cheese layer.

Beat eggs, milk, salt, and pepper together in a bowl; pour over cream cheese layer just below crust edge. Sprinkle mozzarella cheese over egg layer.

Bake in the preheated oven until quiche is set and middle has risen, 40 to 50 minutes. Cool for 5 minutes before slicing.