Meanwhile, in a large skillet cook beef, sweet pepper, onion, and garlic over medium heat until brown, stirring to break up meat as it cooks. Drain off any fat. Stir in tomato paste, water, corn, pickles, mustard, and oregano. Bring to boiling; reduce heat. Simmer, uncovered, for 5 minutes to blend flavors. Stir in remaining 1/2 cup cheese.