Make the Tuna Salad: Peel and chop the eggs, then stir in tuna, ¼ cup of the mayonnaise, relish, mustard, pickle brine, sugar (if using), lemon juice, garlic powder, onion powder, salt, and pepper until combined. Taste test and adjust seasoning as needed.
3 boiled eggs, ½ pound canned or packet tuna, ¼ cup mayonnaise, 3 tablespoons sweet and sour relish, 2 tablespoons mustard, 2 teaspoons pickle brine, ½ teaspoon granulated sugar, ½ teaspoon lemon juice, ¼ teaspoon garlic powder, ¼ teaspoon onion powder, fine sea salt, black pepper