Never heard of cooking fish to pickle them. once cooked, the meat will crumble. Never cooked the vinegar either. Always have used a cold pack. Brining the fish in the salt kills bacteria and firms the meat. Then the vinegar finishes the job. Other than that, this recipe is the basic one I use for salmon or smelt. With salmon I get fancy sometimes and also slice up limes and oranges to add to the mix.
Then I have another recipe for salmon that I use brown sugar instead of white and burgundy wine instead of white wine. and I leave the oranges and limes out of that mix.