In large skillet, brown fryer in oil, cover, and cook until tender (about 15-20 minutes). Drain off excess fat. Cook onion and pepper with chicken until onion is transparent. Drain peaches, reserving syrup. Into 1 cup peach syrup, stir cornstarch, soy sauce, and vinegar. Pour over chicken and cook until clear and slightly thickened. Add peach slices and tomatoes. Heat 5 minutes longer. Serve with hot rice.