Peel and halve the cucumbers. Scrape out the seeds with a teaspoon. Cut cucumber meat into small pieces. Peel and chop onion. Heat the fat in a pot. Sauté the onion and cucumber pieces in it while turning.
Season with salt and pepper. Deglaze with cream and stock and bring to the boil. Cover and cook over medium heat for about 15 minutes. In the meantime cook rice in boiling salted water for about 20 minutes. Cut the salmon off the skin, wash and dice it, sprinkle it with 2 tablespoons of lime juice and salt it a bit.
Sprinkle the sauce thickener into the ragout. Add the fish pieces and cook for about 5 minutes. Wash the dill, chop roughly and stir into the ragout. Season to taste with salt, pepper and remaining lime juice.
Drain the rice and serve with the ragout. Garnish as desired with dill blossom and lime wedges.