For the patties, stir all ingredients together until the mixture starts to come together. Form into 9 small patty shapes. Preheat large nonstick skillet over medium heat. Melt 1/2 the butter and fry up 5 mini patties, being sure to flip as necessary. Melt remaining butter and repeat until all patties are cooked. Set aside.
For the tartar sauce--Stir all ingredients together and serve with tuna.