Preheat oven to 400 °F.
Grease a large baking pan (9x13), cast iron or baking sheet. If using a baking sheet, cover with foil and then grease for easier clean-up.
Season salmon fillets with pepper. Set aside.
In a medium mixing bowl, whisk together the garlic, ginger, soy sauce, brown sugar, sriracha, apple cider vinegar, water, and cornstarch.
Place salmon fillets into a large Tupperware, bowl or resealable bag along with the marinade for 20- 30 minutes in the fridge.
After marinating is complete, remove from the fridge and place salmon fillets in a baking dish. Bake for 12-15 minutes or until flaky once poked with a fork. Bake times may vary depending on the thickness of salmon fillets.
While salmon is baking, transfer the leftover marinade to a small saucepan. Place on medium heat, bring to a boil then reduce heat to a simmer and cook, stirring occasionally until slightly thickened (about 3-4 minutes ) remove from heat and set aside.
Take salmon out and when fish is cooked to your liking, plate and pour teriyaki sauce on top or serve with extra sauce.
Top with green onions and serve with rice and broccoli