No-Bake Tamale Pie

In nonstick 12-inch skillet, heat 2 teaspoons oil over medium-high heat. Add onion and cook 3 minutes or until golden. Stir in garlic; cook 30 seconds. Stir in ground beef and cook, breaking up meat with side of spoon, about 5 minutes or until meat is no longer pink. Add chili powder, cumin, and salt; cook 1 minute. In nonstick 10-inch skillet, heat remaining 2 teaspoons oil over medium-high heat. Add polenta and cook 10 minutes or until golden on both sides and heated through. While polenta cooks, add salsa and frozen corn to meat mixture; cook 3 to 5 minutes to blend flavors. Stir in cilantro. Spoon meat mixture into deep-dish pie plate or shallow 1 1/2-quart casserole. Arrange polenta on top.