Mom used everything in the can except the liquid. You may remove the bones and skin or mix them in with a fork to break them up. Its really your choice but Mom thought the calcium and minerals in the soft bones was worth keeping in this dish.
Mix drained salmon, egg, cracker crumbs, onion, and seasonings well. Use enough cracker crumbs to be able to form salmon mixture into patties that will stick together. This will vary due to the moisture level of the salmon.
Fry patties in vegetable oil until hot all the way through and browned nicely on both sides.