In a small bowl, combine cornstarch and water, mixing until smooth. Add orange juice, soy sauce, and brown sugar, stirring well. Transfer to a saucepan and heat over medium heat for about 3-5 minutes, stirring frequently, until the sauce slightly thickens. Remove from heat and set aside to cool.

Preheat your oven to 400°F (204°C). Prepare baking sheet with oiled foil for easy cleanup.

Place the salmon fillets skin-side down on the prepared baking sheet. Baste each fillet generously with the teriyaki glaze and let sit for a few minutes.

Bake the salmon for around 14 minutes, checking for doneness; it should appear opaque and flake easily. Use a thermometer to ensure it reaches 145°F (63°C).

Baste the salmon again with the teriyaki sauce. Switch your oven to broil and broil for 1 minute until the tops develop a golden char.

Serve the salmon over steamed rice and garnish with sesame seeds, chopped green onions, and red pepper flakes.