In a large mixing bowl, combine one can of well-drained tuna, chopped onion, grated carrot, and sliced green onion. Sprinkle in salt and pepper to taste, then crack in one or two eggs and add flour to bind the mixture. Use a fork to gently blend until all ingredients are evenly combined, ensuring the mixture remains tender.

Once your mixture is well-combined, take small portions and shape them into patties about 2-3 inches in diameter. Aim to create roughly eight uniform cakes.

Heat a generous amount of oil in a non-stick skillet over medium heat. Carefully add the tuna cakes in a single layer, avoiding overcrowding the pan. Fry each cake for about 2-3 minutes until golden brown on one side. Flip and cook for another 2-3 minutes until both sides are crisply browned.

In a small bowl, combine mayonnaise, gochujang, lemon juice, and a dash of sugar. Stir until smooth and well-combined.

Once the cakes are golden and cooked through, place them on paper towels to drain excess oil. Serve warm with the spicy mayo drizzled on top or on the side.