4 6- to 7-ounce salmon fillets
Place vinegar, sugar and both mustards in blender. With machine running, slowly pour in oil and blend until medium-thick sauce forms. (Can be made 1 day ahead. Chill.)
Preheat oven to 375°F. Lightly grease 13 x 9-inch baking dish. Arrange salmon in prepared dish, skin side down. Season with dried thyme, salt and pepper. Spread 1 tablespoon mustard sauce over each fillet, covering completely. Press breadcrumbs onto fish. Bake salmon until cooked through and crumb topping is crisp and golden brown, about 18 minutes.
Using large spatula as aid, transfer salmon fillets to platter. Serve, passing remaining mustard sauce separately.