Grind shrimp, water chestnuts, and green onions into a paste using a meat grinder or blender.

Add salt, sugar, and beaten egg to the paste and mix well.

Spread the mixture evenly on thin slices of white bread.

Sprinkle the bread slices lightly with fine dry bread crumbs.

Cut each slice of bread into four triangles.

Heat 1 inch of oil in a skillet over medium-high heat.

Fry the triangles, shrimp side down first, until golden brown.

Flip the triangles and brown the other side.

Remove the fried triangles and drain on paper towels.

Freeze for later use if desired.

To serve, defrost the triangles and reheat in a 400°F oven for 5 minutes.