In a large mixing bowl, combine the thoroughly drained canned tuna, chopped onion, carrot, green onion, salt, pepper, beaten eggs, and all-purpose flour. Use a fork to mix everything until well incorporated.

With clean hands, take a portion of the tuna mixture and shape it into small patties, about 2-3 inches in diameter.

Heat a non-stick skillet over medium heat and pour in enough oil to coat the bottom. Once the oil shimmers, carefully place the patties in the skillet. Cook each side for 2-3 minutes until they turn golden brown and crispy.

In a separate bowl, combine mayonnaise, gochujang, fresh lemon juice, and sugar. Whisk until smooth and creamy, adjusting heat level to taste.

Once the tuna cakes are cooked, place them on a plate lined with paper towels to absorb excess oil. Serve warm with the zesty spicy mayo.