The tiny bit of rice won't hurt.
Cut the stem top off the bell peppers and remove the seeds. Also if necessary, cut a little off the bottom of the pepper to allow it to stand still without moving. Cook 4 peppers in a small amount of water (or juice from tomatoes) in microwave, until slightly tender. Combine rice, diced peppers (cut from pepper tops), onion, tomato, hamburger meat, and salt/pepper and saute in olive oil until vegetables are tender. Stuff the 4 green peppers with mixture. Any remaining vegetable mixture should be placed around stuffed peppers. Bake in 350°F oven for 30 minutes. Remove from oven, top with cheese, and serve.