In a small bowl, mix together the ingredients for the seasoning mix/marinade.
Place the salmon fillets in a shallow dish or plastic bag and pour the marinade over them, ensuring they are evenly coated. Let the salmon marinate in the refrigerator for at least 30 minutes.
Preheat your oven to 400℉ and spray a large baking sheet with the non-stick cooking spray, or line with parchment paper or aluminum foil.
While the oven is preheating and the salmon is marinating, slice the bell peppers and onion into thin strips and arrange them on the prepared baking sheet.
Season your sliced vegetables with the minced garlic and a little bit of salt and pepper to taste.
Once the salmon has finished marinating, remove it from the refrigerator and place the fillets on the baking sheet on top of the sliced veggies.
Drizzle any remaining marinade over the dish, ensuring it is evenly coated.
Bake in the preheated oven for 12-15 minutes, or until the salmon is cooked through and the veggies are tender.
Remove the sheet pan from the oven and garnish with optional toppings such as cilantro, avocado, or lime juice. Enjoy!