Make the Shrimp Filling: Finely chop or pulse the shrimp in a food processor until a coarse paste forms. Transfer to a bowl and mix in cilantro, potato starch, garlic powder, salt, egg white, and sesame oil. Stir until well combined.
Assemble the Toasts: Spread a thin, even layer (no more than ½ inch thick) of the shrimp mixture on one slice of bread. Top with another slice and press gently. Trim crusts if preferred.
Butter the Bread: Brush both sides of each sandwich with melted butter.
Cook the Toasts: Air Fryer Method: Preheat air fryer to 360°F (180°C). Place toasts in the basket in a single layer. Air fry for 10 minutes, flip, then cook for another 5–7 minutes until golden and fully cooked.
Oven-Baked Method: Preheat oven to 400°F (200°C). Place toasts on a parchment-lined baking sheet. Bake for 12–15 minutes, flipping halfway through. For extra crispiness, broil for 1–2 minutes at the end.
Make the Sauce: In a small bowl, whisk together mayonnaise and sweet chili sauce until smooth. Set aside.
Serve: Slice the shrimp toast into halves or quarters. Drizzle with bang bang sauce or serve it on the side for dipping.
