Cut the salmon fillets into 1- and 1/4-inch (3-centimeter) cubes while they are still partially frozen (if using frozen salmon). Soak in lemon juice and salt for half an hour. If using fresh salmon, the soaking can be skipped.

Mix all marinade ingredients in a bowl and brush onto the fish cubes.

Heat a nonstick pan very well and sear the fish on all sides until done. Alternately, you can bake the fish at 450 degrees fahrenheit for 20 minutes.

To prepare the mushrooms, heat oil in a frying pan or wok and saute the onion, garlic, and pepper lightly.

Add the mushrooms and stir-fry for five minutes. Add the soy sauce and the remaining marinade from the fish.

Stiry fry for two to three minutes and remove from flame. Taste and adjust seasoning.

Transfer mushrooms to a plate or glass. Skewer the fish chunks and place over the mushrooms.

Garnish with scallions and serve.