Preheat oven to 375°.
To prepare cakes, combine first 3 ingredients in a food processor; process until smooth. Stir in 1/2 cup breadcrumbs, 1/4 cup green onions, and salt.
Divide mixture into 24 equal portions, shaping each into a 1/2-inch-thick patty. Place 1/2 cup breadcrumbs in a shallow dish. Dredge patties in breadcrumbs. Place patties on a baking sheet coated with cooking spray. Bake at 375° for 14 minutes, turning after 7 minutes.
To prepare toppings, combine sour cream and 1/4 cup green onions in a small bowl. Combine avocado, tomato, and juice in a small bowl. Top each patty with 1 teaspoon green onion cream and 1 teaspoon avocado salsa.