Prepare the Teriyaki Sauce: In a small saucepan, combine soy sauce, honey (or maple syrup), rice vinegar, sesame oil, garlic, and ginger. Stir well and bring to a simmer over medium heat. If you prefer a thicker sauce, mix cornstarch and water in a small bowl, then add it to the saucepan. Continue simmering for 3-4 minutes, until the sauce thickens.
Preheat the Oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly grease it.
Prepare the Salmon: Place the salmon fillets on the prepared baking sheet. Spoon some of the teriyaki sauce over each fillet, coating it evenly.
Bake the Salmon: Bake the salmon in the preheated oven for 12–15 minutes, or until the salmon is cooked through and easily flakes with a fork.
Serve: Once baked, drizzle the remaining teriyaki sauce over the salmon and garnish with sesame seeds and green onions, if desired. Serve immediately with steamed rice, vegetables, or a side salad.