Place meat and onion in a 10 1/2-inch ovenproof skillet. Cook over medium-high heat until meat is browned, stirring until it crumbles. Drain mixture, and pat dry with paper towels. Wipe drippings from skillet with a paper towel.
Return meat mixture to skillet. Add salsa and next 6 ingredients. Bring to a boil; cover, reduce heat, and simmer 30 minutes.
Combine cornmeal and next 5 ingredients in a bowl; make a well in center of mixture. Combine egg substitute, milk, and oil; add to dry ingredients, stirring just until dry ingredients are moistened.
Pour batter over meat mixture in skillet. Bake, uncovered, at 400° for 10 minutes or until cornbread is golden. Sprinkle with cheese, and let stand 5 minutes or until cheese melts.