Tuna Burgers with Fresh Herbs

In a bowl, mix the white wine vinegar and sugar with a fork until the sugar is dissolved.

Slice the cucumber with a vegetable peeler. Let the cucumber marinate in the vinegar mixture in the refrigerator for at least 30 minutes.

Make the lemon mayonnaise by mixing the mayonnaise with the lemon juice and zest.

Meanwhile, make the sauce. Snip the parsley from the plant and chop finely. In a bowl, mix the garlic, lemon juice, pickle, capers, red chili, flat-leaf parsley, and 100 milliliters of olive oil with a fork.

Heat a grill pan or frying pan over medium heat. Slice the buns in half lengthwise and toast the inside of the buns in the grill pan for 2 minutes until golden brown.

In a large bowl, mix the tuna, lemon zest, egg, red chili, shallot, chives, and breadcrumbs (add enough breadcrumbs so the mixture doesn't feel sticky). Season with salt and pepper.

Divide the mixture into 4 equal balls with your hands. Flatten them to form burgers. Brush both sides of the burgers with olive oil using a pastry brush.

Heat the grill pan or frying pan over medium-high to high heat. Grill the tuna burgers on each side for 3-4 minutes, depending on the thickness.

Spread half of the lemon mayonnaise on the bottom of each bun.

Place a leaf of iceberg lettuce and a tuna burger on each bun. Top with 1 tablespoon of the sauce. Add the tomato slices and marinated cucumber. Spread the remaining lemon mayonnaise on the other half of the bun and place it on top, with the mayo side facing the cucumber.

Serve the fish burger with extra sauce on the side.