In a large mixing bowl, combine drained canned tuna, chopped green onions, whisked egg, soy sauce, arrowroot powder, mayonnaise, minced garlic, and salt and pepper. Mix thoroughly until well incorporated.

Divide the mixture into equal portions and shape each into patties, about 2 inches in diameter. Place the patties on a plate lined with parchment paper.

Heat avocado and sesame oil in a nonstick skillet over medium heat. Fry the patties for 2 to 3 minutes on each side until golden brown.

While the cakes cook, combine mayonnaise, lime juice, Sriracha, and salt in a small bowl to make the spicy mayo.

Once cooked, remove cakes from skillet and serve with spicy mayo drizzled on top or on the side.