To make the salmon skin chicharrones remove the skin from the fillet. Make sure to remove any flesh left attached to the skin. Place the skin (outside part down) on a baking tray lined with parchment paper and dry in a static oven (no fan) at 150F (or lowest temperature) for at least 4 hours. You can open the oven around the 4 hours mark to check if the skin is dry enough. If it still has a lot of oil attached you can use a paper towel to dry it off. Keep in the oven until ready to fry. Fry at 350/375F. Drop the skin in the hot oil, it should puff up in a few seconds. If it doesn’t puff right away, you may have to fry it twice.
Drain in a paper towel. Set aside.
To make the salmon burgers, cut 3 filets of salmon in small pieces, around a ¼ of an inch cubes and set aside in a bowl. The last filet can be chopped in bigger chunks and put in a food processor with the shallot (roughly chopped), capers, hot sauce, breadcrumbs and mustard. Run the food processor until you get a paste. Add the paste to the small diced salmon along with 1 cup of mayo, fresh parsley and lemon zest. Season with salt and pepper
Mix everything together and form 4 hamburgers.
For the tartar sauce, just mix 1 cup of mayo with the pickles, dill, lemon juice, honey, salt and pepper.
Toast the brioche buns in a pan or griddle with a drizzle of olive oi until golden brown. Set aside.
Cook to the hamburgers in a very hot cast iron or a griddle. Drizzle with some olive oil, add the burgers and cook on high heat a few minutes per side; then lower the heat and cover for a few more minutes to make sure the inside gets cooked and hot.
To serve, spread some tartar sauce on the bottom part of the bun, place a few leaves of lettuce per bun, then add the salmon burger, some more sauce and top with the crispy salmon skin.