Mix tuna, stuffing mix, cheese, mayo, relish and water in a bowl. Cover the bowl and refrigerate for 10 mins.
Heat a large nonstick skillet sprayed with cooking spray on medium heat. Scoop tuna mixture, using about 1/3 cup for each cake into skillet in batches. Gently flatten cakes using a spatula. Cook for 3 min on each side or until they're golden brown on both sides. Turn them carefully.