In a small bowl, combine the yogurt, mayonnaise, lemon juice, mustard, salt and pepper. Whisk until smooth, then add the dill and parsley and stir to combine. Set aside.
Once rinsed and drained place the chickpeas in a large bowl, add the celery and scallions and toss.
Pour the dressing over the salad, toss well, and sprinkle with more dill and parsley and serve.
Can be served at room temperature or stored in the refrigerator and served cold.
