Mix ingredients together in a shallow dish.
Add salmon fillets, turn to coat well and leave to marinate in the fridge overnight.
Preheat grill to high. Line the grill pan with foil and oil well.
Place salmon in pan and grill for one minute on each side.
Salmon will be rare in the middle, so grill for a few minutes longer if you prefer it well done.
Mix ingredients together.
Toss watercress in the dressing and arrange leaves in the centre of four plates.
Heat oil in a pan and deep-fry ginger until crisp.
Place the salmon on the watercress leaves, drizzle with dressing and scatter deep-fried ginger over.
Tip:A combination of apple, carrot and pineapple juice and a small cube of ginger is said to cleanse the body. Serve with lots of crushed ice.