1Remove fat from beef. In 3 1/2- to 4-quart slow cooker, place beef. Top with onion. In small bowl, mix teriyaki glaze and orange peel; pour over beef and onion.
2Cover and cook on Low heat setting 8 to 10 hours.
3Remove beef from slow cooker; place on cutting board. Cover to keep warm.
4In small bowl, mix water and cornstarch; gradually stir into juices in slow cooker. Increase heat setting to High. Cover and cook about 15 minutes, stirring occasionally, until sauce has thickened. Cut beef across grain into thin slices. Serve sauce with beef.