Heat 1 teaspoon oil in a large nonstick skillet over medium-high heat. Add onion; sauté 5 minutes. Spoon onion into a bowl. Add bell pepper, olives, water, and 1 teaspoon thyme; stir well. Cover and refrigerate at least 2 hours.
Combine 1 teaspoon olive oil, 2 teaspoons dried thyme, paprika, salt, garlic powder, and ground red pepper. Rub paprika mixture over both sides of fillets. Place fillets on a grill rack coated with cooking spray; grill 5 minutes on each side or until fish flakes easily when tested with a fork. Serve with relish.