Preheat oven to 350 degrees F. Cook rice according to package directions; set aside seasoning packet.
In a large skillet on medium-high heat, brown the beef with chopped onion and garlic until fully cooked.
Meanwhile, cut tops off of bell peppers and remove seeds. In a medium sauce pan, place the peppers in about 2-3 inches of boiling water. Cover and cook for several minutes, or until peppers are semi-soft. Remove peppers from water and set aside to drain and cool.
Drain any excess fat from ground beef and return to skillet on low heat. Add tomatoes, rice and rice seasoning. Stir mixture, adding the oregano and salt and pepper to taste.
When mixture is thoroughly heated remove skillet from heat. Place peppers in a small baking dish and fill with meat mixture. Top with cheese, if preferred. Heat for 5-8 minutes.