To prepare polenta, bring milk to a boil in a medium saucepan; gradually add polenta, stirring constantly with a whisk. Reduce heat, and cook 5 minutes or until thick, stirring constantly; stir in 1/4 teaspoon salt. Remove from heat. Stir in cheese; cover and keep warm.
To prepare the fish, heat a large nonstick grill pan over medium-high heat. Combine oil, paprika, garlic powder, 1/2 teaspoon salt, and pepper in a bowl, stirring well. Rub fish evenly with oil mixture. Coat pan with cooking spray. Add fish to pan; cook 4 minutes on each side or until fish flakes easily when tested with a fork or until desired degree of doneness.