Cut the salmon into 1 cm strips and mix with 2-3 tablespoons of yoghurt. Chill for half an hour, if you have time.
Beat the eggs in a separate bowl (no need to add salt because the smoked salmon is salty enough).
In a shallow pan fry the eggs in melted butter or oil for 1-2 minutes, stirring constantly, as if you were making scrambled eggs. When half- cooked, add the marinated salmon, spread evenly.
Cook, under cover for 5-10 minutes. The omelette will rise a bit and will cook in the steam.
Meanwhile: turn on the grill.
Sprinkle with cheese and grill for about a minute until golden brown.
Serve warm.