Heat 2 teaspoons oil in a large nonstick skillet over medium heat.
Add onion and the next 6 ingredients (onion through pepper). Cover and cook 10 minutes or until onion is wilted, stirring occasionally. Set aside; keep warm.
Place fillets in a shallow baking dish coated with cooking spray.
Brush fillets with 1/2 teaspoon oil; sprinkle with breadcrumbs and 1/8 teaspoon salt.
Bake at 450 for 12 minutes or until fish flakes easily when tested with a fork.