Rinse the fish, remove scales and innards. Cut into steaks.
For the marinade, cut the onion into rings and mash it with your hands so that the onion gives a little juice. Add Adyghe salt, pepper, mayonnaise, soy sauce and sprinkle with lemon juice.
Put the salmon steaks in a form with marinade and refrigerate for 1 hour to marinate.
Put the marinated steaks on the grill, lay the onion on top. Fry on the grill until cooked through for about 15-20 minutes (depending on the thickness of the steaks and the heat of the coals).