Finely dice the cucumber and
place in a sieve over a bowl.
Sprinkle with salt and leave to
drain for 1 hour.
Rinse with cold water and pat dry
with kitchen paper.
Stir the drained cucumber into
the yogurt and add the mustard, spring onion, and
Season to taste with salt and
Preheat the oven to 400°F.
Arrange the salmon fillets in a
shallow baking dish, brush with oil, and season to
taste with salt and pepper.
Sprinkle the salmon with lemon
juice and roast for 8–10 minutes.
Depending on the thickness, until
just cooked through but still moist inside.
Remove from the oven and stir the
juices from the dish into the cucumber sauce.
Serve the salmon hot or cold,
with the sauce spooned over it.
The sauce can be prepared up to 2 days in advance,
covered, and chilled. The salmon can be cooked up to
24 hours in advance if served cold. Chill until