Method
Preheat oven to 180°C/fan 160°C/gas 4.
Place the cucumber in a sieve over a bowl and leave to drain for 30 minutes. Press down with the back of a tablespoon to squeeze out excess water. Pat dry the grated cucumber with kitchen paper.
In a small bowl, stir together the cucumber, sour cream, yoghurt, dill, 1 tbsp lemon juice and salt and pepper to taste. Set aside.
Melt the butter and oil in a frying pan. Add the salmon skin-side down, season with salt and pepper and squeeze over a little lemon juice. Cook for 2-3 minutes, then gently turn the salmon over and cook for a further 1-2 minutes. Squeeze over a little more lemon juice and taste to check the seasoning. Place in the oven and bake for 3-4 minutes or until just cooked through.