Preheat the oven to 450 degrees F. Line a baking sheet with parchment paper. Brush the parchment with the oil. Place the hazelnuts, sage, paprika, salt and pepper in the bowl of a food processor and pulse until the hazelnuts are finely chopped. Spread the hazelnut mixture into a wide, sided dish. Brush and thoroughly coat the turkey cutlets with the mayonnaise. Set a cutlet on the hazelnut mixture and coat on both sides, gently pressing on the hazelnut mixture to help it adhere. Set the cutlet on the baking sheet. Repeat with the remaining cutlets. Bake the cutlets for 5 minutes, and then flip over. Bake for 5 to 7 minutes more, or until cooked through.