Preheat oven to 400. Lightly coat a baking sheet with cooking spray.
In a large mixing bowl, lightly mash the avocado.
Add the tuna, bread crumbrs, red onion, cilantro, ilime juice, hot sauce, garlic powder, salt, and egg.
Mix until the ingredients are fairly well combined.
Form into 6 patties, then arrange on the prepared baking dish. Bake for 10 minutes, flip, then continue baking until the outsides are lightly crisp and the cakes are cooked through (about 10 additional minutes).