Cook the lentils in boiling water for 8-10 minutes. Drain and leave to drain. Divide cauliflower into small florets and simmer in boiling salted water for about 5 minutes. Drain and let drain. Peel and finely chop the onion.
Deseed, wash and chop the chilli.
Whisk chilli, onion, mustard, vinegar and oil. Season with salt, pepper and 1 pinch of sugar. Mix lentils and cauliflower with the vinaigrette and season to taste.
Wash the salmon, dab dry. Boil up apple juice with lemon juice in a pan. Season with salt and pepper. Add the salmon fillets, cover and steam over medium heat for about 5 minutes. Cut cress from the bed and mix into the salad.
Serve salmon with salad.