For the smoked trout mousse on cucumber cheese, cut the fish into coarse pieces. Puree with crème fraîche in a hand mixer.
Wash and dry the cucumber. Cut into 1/2 cm thick slices. Fill the trout mousse into a piping bag with a star-shaped nozzle. Squirt onto the slices.
Garnish the smoked trout mousse on cucumber dumplings with dill.