Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a small saucepan, whisk together the soy sauce, maple syrup, rice vinegar, sesame oil, garlic, and ginger.
Bring to a simmer over medium heat, then stir in the cornstarch slurry (cornstarch mixed with water).
Let the sauce bubble gently for 1–2 minutes until slightly thickened. Remove from heat.
Place salmon fillets skin-side down on the prepared baking sheet.
Spoon a generous amount of the teriyaki sauce over each fillet, reserving a little for serving later.
Bake for 12–15 minutes, or until the salmon flakes easily with a fork.
Drizzle with extra sauce and sprinkle with scallions and sesame seeds before serving.