Grease a large rimmed baking sheet (cover with foil and then grease for easier clean-up). Preheat oven to 400˚F.
Combine sauce ingredients and stir until sauce thickens.
Place individual salmon slices in a mixing bowl. Pour the sauce over the salmon, cover with plastic wrap and let marinate 20 minutes (at room temp or refrigerated).
Transfer salmon to prepared baking sheet (keep the marinade). Bake at 400 for 12-16 min or until salmon is flaky and cooked through, bake times may vary by thickness of salmon.
While salmon is baking, transfer remaining marinade to a small saucepan and bring to a boil then reduce heat to a simmer and cook, stirring occasionally until slightly thickened (3-4 min) then remove from heat.
Once salmon is out of the oven, brush with teriyaki syrup, then sprinkle with chopped green onion and sesame seeds as desired.