Preheat oven to 400 degrees. Combine stock and mustard in a medium saucepan; bring to a boil. Gradually add polenta, stirring constantly with a whisk. Reduce heat to low and cook 20 minutes, stirring frequently. Stir in Parmesan cheese, oregano and 1/4 teaspoon salt. Place panko and next 4 ingredients (through pepper) in a large skillet; cook over medium heat for 3 minutes or until toasted, stirring frequently. Place panko mixture in a shallow dish. Combine 2 tablespoons water and egg in a shallow dish. Place flour in a shallow dish. Sprinkle fish with remaining 1/4 teaspoon salt. Dredge fish in flour; dip in egg mixture. Place fish in panko mixture, turning to coat. Arrange fish on a baking sheet coated with cooking spray. Bake at 400 degrees for 15 minutes or until done. Serve with lemon wedges and polenta.
Place 6 cups of baby spinach leaves in a large bowl. Heat a small skillet over medium-high heat. Add 2 tablespoons olive oil; swirl to coat. Add 1 teaspoon minced garlic and 1/2 cup grape tomatoes; cook 1 minute, stirring constantly. Add 2 tablespoons cider vinegar, 1 teaspoon honey, 1/2 teaspoon freshly ground black pepper and 1/4 teaspoon salt, stirring with a whisk. Add vinegar mixture to spinach; toss to coat.