Use a vegetable peeler to shave the cucumber lengthwise into thin ribbons. Rotate the cucumber once you reach the seedy core to avoid watery and bitter ribbons.

Place the ribbons in a bowl with white wine vinegar, sugar, and salt. Toss to coat and set aside for at least 15 minutes to pickle and soften lightly. Drain off any excess liquid before serving.

Roughly chop the salmon fillets into chunks and place them along with the other burger ingredients in a food processor. Pulse the mixture in short bursts until it just comes together, aiming for a coarse, textured mix.

Shape the mixture into 4 burger patties, around 2cm thick. Place them on a plate or tray, cover, and refrigerate for 15-30 minutes to firm up.

Heat oil in a large frying pan over medium heat. Cook the patties for 3–4 minutes per side, or until golden brown and just cooked through. Transfer them to a plate and allow to rest for a few minutes.

In a mixing bowl, add the feta, yoghurt, lemon juice, dill, and capers. Mash with a fork until the mixture becomes smooth and creamy.

Spread a generous layer of the feta mixture onto the base of each bun. Top with lettuce, burger patty, more feta spread, tomato, pickled cucumber ribbons, and capers.