Cook rice according to package directions, using reserved tomato liquid in place of water. Set aside any remaining reserved tomato liquid.
Cut off tops of peppers and remove seeds. Cook, uncovered, in boiling water for 3 minutes. Drain and set aside.
Chop tomatoes. In medium mixing bowl, combine with remaining ingredients, cooked rice and 1/4 cup of the reserved tomato liquid, stirring gently. (Use water, if not enough reserved tomato liquid.)
Spoon rice mixture into peppers. Place in shallow baking dish. Add water just to cover bottom of dish. Cover with glass cover for baking dish or with foil.
Bake at 350° F for 30 minutes or until hot and peppers are tender. Serve hot with tomato sauce, if desired.