Mince aromatics:
In a food processor, pulse scallions, garlic, and cilantro until finely minced.Process shrimp paste:
Add two-thirds of the shrimp, egg white, soy sauce, and sesame oil; process until a coarse paste forms.Transfer paste to bowl:
Transfer the paste to a medium bowl.Dice and fold shrimp:
Dice the remaining shrimp into 1/4-inch cubes, season with salt and pepper, then fold into the paste.Assemble and coat triangles:
Evenly distribute the shrimp mixture over the bread slices. Press each slice, shrimp side down, into sesame seeds to coat. Cut each slice into 4 triangles.Fry triangles until crisp:
Heat neutral oil in a skillet over medium-high heat. Fry the triangles in batches until golden and crisp, about 2-3 minutes per side. Flip as needed.Drain and serve warm:
Drain on paper towels and serve warm.