How to Make It
Place chiles, lemon juice, orange juice, salt, garlic, and ginger in a blender; process until smooth, about 45 seconds. With blender running, slowly add oil in a thin, steady stream until sauce thickens or emulsifies, about 30 seconds.
Place tuna slices in a single layer on a large rimmed platter. Pour sauce over tuna. Sprinkle with chips, peanuts, sesame seeds, and scallions. If desired, sprinkle with additional salt to taste.