Halve the cucumber lengthways and scoop out the seeds. Slice into half moons and put in a sieve, sprinkle with a little salt and leave to drain for 10 minutes.
Season the salmon fillets and put on a plate. Steam for 6 minutes or cover with clingfilm and microwave for 4 minutes or until cooked through. Rinse the cucumber and pat dry. Flake the salmon, mix with the cucumber, crème fraîche and dill and season with black pepper. Serve with the toast.