Bring a large pot of salted water to a boil and set a bowl of ice water nearby. Drop the green beans into the boiling water and blanch for 2 minutes. Remove the beans and immediately immerse in the ice water long enough to cool completely, about 15 seconds. Drain and place on paper towels or a kitchen towel to dry.

In a large bowl, whisk together the olive oil, apple cider vinegar, garlic, mustard, honey, and salt. Add the onion, chickpeas, kidney beans, celery, green beans, and parsley, and toss to coat. Chill for 1 hour, then serve.