In a large bowl, combine chopped shrimp, 1/2 cup panko, 1/4 cup mayonnaise, egg, green onions, garlic, mustard, lemon juice, Old Bay, salt, and pepper.
Shape the mixture into small patties and coat each with additional panko breadcrumbs.
Heat olive oil in a skillet over medium heat. Fry the shrimp cakes until golden brown and cooked through, about 3–4 minutes per side.
In a small bowl, whisk together 1/2 cup mayo, lemon juice, orange juice, minced garlic, and a pinch of salt and pepper to make the citrus aioli.
Serve the shrimp cakes warm with a side of citrus aioli for dipping.