Grease an 8 x 8 x2-inch baking dish. Heat oil in skillet; brown onion and ground beef. Stir n cheese, seasonings and rice. Set aside.
With a sharp knife, cut a 14-inch slice from top of tomatoes. Cut around inside of tomatoes, being careful not to cut through the bottom. Scoop out center pulp. Sieve the tomato pulp and set aside the liquid. Sprinkle each tomato with salt. Lightly fill the tomatoes with filling. Place tomatoes in baking dish. Pour tomato juice over tomatoes.
Bake at 375°F for 20-25 minutes. Garnish with parsley.