For polenta, in a large saucepan bring 3 cups water to boiling. In a bowl combine cornmeal, 1 cup cold water, and 1/2 teaspoon salt. Stir cornmeal mixture slowly into boiling water. Cook and stir until mixture returns to boiling. Reduce heat to low. Cook 5 to 10 minutes or until mixture is thick, stirring occasionally. (If mixture gets too thick, stir in additional water.) Meanwhile, in a large skillet combine beans, undrained tomatoes, and salsa. Bring to boiling; reduce heat. Simmer, uncovered, 10 minutes, stirring frequently. Stir 1/2 cup of the cheese into polenta. Divide polenta among four shallow bowls. Top with bean mixture and remaining cheese.