In a medium mixing bowl, combine salmon, half of the cornflake crumbs, mayonnaise, egg, green onion and mustard.
Shape into four patties.
Place remaining cornflake crumbs in a bowl. Coat each patty evenly in crumbs, pressing lightly to coat both sides.
Arrange patties in a square casserole dish. Cover with microwave-safe plastic wrap. Microwave on high for 4½ to 6 minutes or until firm and hot, rotating casserole dish once.
Brown the patties in a lightly-oiled pan.
Serve salmon patties topped with tartar sauce, if desired.