To make teriyaki sauce: Peel and chop ginger to yield 3 tablespoons. In a small saucepan simmer sauce ingredients, stirring until sugar is dissolved, until reduced to about 1 cup and cool to room temperature in a metal bowl set in a larger bowl of ice and cold water.
In a baking dish large enough to just hold salmon steaks in 1 layer, marinate salmon in sauce, turning to coat, 15 minutes.
While salmon is marinating, cut carrots in half and slice into 1/4-inch slices. Peel onions and slice into 1/4-inch slices. In a large saucepan of boiling salted water, blanch vegetables 2 minutes, or until crisp-tender, and drain in a colander. Transfer vegetables to a bowl of ice and cold water to stop cooking and drain well.
In a 10-inch heavy skillet (preferably cast iron) heat oil over moderately high heat until hot but not smoking. Transfer salmon to skillet with a metal spatula, letting excess sauce drip off and reserving, and reduce heat to moderate. Saute salmon, turning once, until just cooked through and browned well, about 2 1/2 minutes on each side, and transfer to 2 plates. Pour off oil and cook vegetables, stirring, 1 minute. Add reserved sauce and boil, stirring, 1 minute, or until thickened.
Spoon vegetables and sauce over salmon and garnish with scallion greens.
Recipe courtesy of Gourmet Magazine