Mix tuna, egg, and crushed pork rinds in a small bowl until well combined
Heat non stick pan over medium high and melt butter
Form tuna mixture into 3-4 patties and sauté on one side for 2-4 minutes. Flip over and sauté another 3-54 minutes until tuna cakes are golden brown
Drizzle cakes with Peperoncini juice and serve warm