Rinse the two organic cucumbers thoroughly under cold running water. Trim the ends and use a vegetable peeler or mandoline to create long, thin ribbons from the vegetables. Finely chop the fresh dill. Take the smoked mackerel, remove the skin if necessary, and flake the fish with your hands into large pieces. Carefully check the fish for any remaining bones and remove them.
Get a large mixing bowl and add the cucumber ribbons. Pour in the two tablespoons of apple cider vinegar. Sprinkle the finely chopped fresh dill and a pinch of turmeric over the cucumber. Mix everything together well so the liquid and spices are evenly distributed over the vegetables.
Add the flaked pieces of smoked mackerel to the cucumber salad. Gently fold the fish through, ensuring the texture of the mackerel is preserved and it doesn't turn to mush. Taste the mixture and season further with a pinch of Celtic sea salt.
Divide the prepared salad into portions on plates. Serve the dish immediately chilled, or cover and refrigerate until serving so the flavours can blend further.