In a medium pan bring water to a boil. Add barley, reduce heat, cover and simmer until tender. Drain off excess water, rinse with cold water and let cool.
Meanwhile, whisk together ingredients for dressing and set aside.
In a large bowl add cooked and cooled barley, chickpeas, red onion, red grapes, celery, parsley and nuts/seeds. Add dressing, toss to coat and enjoy :)