Rinse the cucumber and peel in strips. Halve the cucumber and cut into slices. Chop cranberries finely. Rinse ling fish fillet, dab dry and cut into pieces.
Heat the oil in a coated pan. Lightly fry the ling fish in it. Remove from the pan. Deglaze with stock and pour on the cream. Simmer for 2-3 minutes. Add the sauce thickener and let the sauce boil for 1 minute while stirring.
Season to taste with lemon juice, salt and pepper.
Add fish fillets, cucumber and cranberries to the sauce. Let the fish fillets simmer in the sauce for about 4 minutes at low heat.
Rinse dill, shake dry and chop. Season the sauce again and stir in the dill. Serve with rice.