The Alaskan salmon burger is defined by a problem that a beef burger never has to solve: the patty does not want to hold together. Wild Alaska salmon, sockeye or coho or king, is lean fish with very little intramuscular fat, so a patty ground or chopped from it has almost nothing to bind it as it cooks. It firms up, it does not fuse. Every decision in this sandwich is about answering that, which is why the good versions are built around a binder and a light hand rather than around the fish alone. The fish supplies a clean, mineral, faintly oceanic flavor; the construction is what keeps it on the bun.
The craft is in the chop and the bind. Salmon for a burger is not pureed, because a smooth paste cooks dense and rubbery; it is hand-chopped or coarse-ground so some pieces stay in distinct flakes and the patty has texture. A binder goes in to do the work the fat will not: egg, a little breadcrumb or panko, sometimes a spoonful of mayonnaise, enough to set the patty without turning it into a cake. It is cooked hot and fast and pulled while the center is still just translucent, because lean fish goes from moist to dry in the span of a minute. The bun is soft and the dressing is cool and acidic, a dill or lemon mayonnaise, capers, raw onion, because the fish brings no fat to cut and the sandwich would read flat without that sharp counter.
The variations stay close to the same lean-fish logic. A teriyaki or soy glaze leans the patty toward the Pacific Northwest table; a panko-crusted version fries the outside for a shell the lean interior cannot make on its own; a flaked rather than ground patty keeps the fish in large pieces bound only at the edges. The canned-salmon croquette and the richer farmed-salmon burger are close relatives that change the fish itself rather than the build. Each of those deserves its own article rather than being crowded in here.