Peel and devein the shrimp, then finely chop them.
Finely chop the onion and green onion.
Mix the chopped shrimp, onion, and green onion with egg white, salt, pepper, and starch.
Spread the shrimp mixture thinly over the bread slices.
Heat a generous amount of cooking oil in a pan and place the bread with the shrimp side down over medium-low heat.
Once one side is golden, flip and toast the bread side until done.