Teriyaki Salmon Sheet Pan Dinner

A complete, lightning-fast meal cooked on a single sheet pan. The veggies are tender-crisp, while the salmon is irresistibly creamy. Ingredients and bake times are listed below:
For the vegetables:
Colorful bell peppers (3 medium or 2 large)
1 medium red onion
Olive oil
For the salmon:
1/2 to 3/4 cup bottled Teriyaki sauce
Dash red pepper flakes
1 heaping tablespoon cornstarch
2-4 salmon fillets (I used Scottish organic salmon), skin removed
Optional garnish for the fillets: plain or toasted sesame seeds
Oven temp: 425°F. Cook vegetables for exactly 15 minutes. While the veggies cook, marinate the salmon. Add salmon to veggies, and cook for exactly 10 minutes.