Preheat the oven to 375 degrees F.

Place a silpat mat on a baking sheet. Place 6 (1/4-cup) mounds of Parmesan cheese on the mat and gently tap down until each mound is flat. Bake for 7-10 minutes, until golden and bubbly. Use a thin spatula to transfer the Parmesan to a muffin tin. Gently mold Parmesan Cup to fit the shape of the muffin tin. Let cool until firm, about 5-6 minutes. Continue with the remaining Parmesan cheese.

Tuna salad: combine the rest of the ingredients in a bowl then divide between cups. Serve immediately.