Heat oven to 425°F. Line 15x10x1-inch pan with foil; spray foil with cooking spray.
In 2-quart saucepan, stir together teriyaki sauce, preserves, water, oil, gingerroot, mustard and garlic. Heat to boiling over medium-high heat, stirring occasionally. Reduce heat to low; simmer uncovered 5 minutes, stirring occasionally, until slightly thickened.
Rinse salmon fillets; pat dry with paper towels. Place salmon, skin sides down, in pan. Spoon 1/2 cup sauce mixture over salmon.
Bake uncovered 20 to 25 minutes, rotating pan after 10 minutes, until salmon flakes easily with fork.
Meanwhile, heat remaining sauce mixture to boiling. Reduce heat to low; simmer uncovered 5 minutes, stirring occasionally, until thickened and reduced to about 1/2 cup.
Carefully transfer salmon to serving platter. Drizzle with thickened sauce mixture. Sprinkle with onions and sesame seed.