PLACE the salmon in a bowl with 1 teaspoon of ginger and 1 tablespoon of soy sauce and mix well to coat evenly. COVER and marinate in the fridge for at least 20 minutes. WHILE the salmon marinates, mix together the remaining 2 teaspoons of ginger, 2 tablespoons of soy sauce, the oyster sauce, water and brown sugar in a small bowl. HEAT a wok or large frying pan over a high heat. ADD the salmon and stir-fry for 2 minutes. REMOVE the salmon and set aside on a plate. HEAT the oil in the wok and stir-fry the yellow pepper and green beans for 6 minutes. ADD the scallion and stir-fry for 1 minute. RETURN the cooked salmon to the wok then, stirring continuously, add the sauce mixture then immediately remove from the heat. SERVE with rice or noodles.