In a medium saucepan, combine cornstarch and water, stirring until dissolved. Then, add orange juice, orange zest, soy sauce, brown sugar, minced ginger, minced garlic, and sesame oil. Heat over medium while whisking continuously until thickened, about 3-5 minutes.

Preheat your oven to 400°F (200°C) and line a baking sheet with aluminum foil, lightly greasing it.

Place salmon filets, skin-side down, on the baking sheet. Baste with half of the teriyaki sauce mixture.

Bake the salmon for approximately 14 minutes, or until it flakes easily with a fork.

Remove and baste again with the remaining teriyaki sauce. Switch to broil and char for an additional 1-2 minutes.

Transfer salmon to a serving platter and garnish with sesame seeds, red pepper flakes, and green onions.