Add crawfish tails, green onions, mayo, and both cheeses to a bowl. Gently combine all ingredients together with a spoon. Season crawfish mixture with Tony Chachere’s Seasoning and stir until combined.
Flatten out each biscuit with hands or a rolling pin until they are rectangular in shape. Place a tablespoon of the crawfish mixture in the center of the flatten biscuit. Use your hands to close all sides of dough over the crawfish mix, and seal all creases.
Heat oil to 375 in a large heavy pot and add 4 beignets at a time. Fry until golden brown on all sides. Set aside once all beignets are fried.
Combine parmesan cheese and cayenne pepper, and sprinkle over the finished beignets.