Preheat oven to 400 degrees and line a rimmed baking sheet with parchment paper.
Rinse and drain chickpeas, then gently rub them between two kitchen towels to remove excess moisture. This will also release the outer layer of skin on some of the chickpeas. I remove these and discard them.
Transfer chickpeas to parchment lined baking sheet. Spray with cooking spray and sprinkle generously with garlic salt. Bake for 20-30 min, removing 2-3 times during cooking to stir and apply another coating of cooking spray and garlic salt. Allow to cool a few minutes on pan before adding to salad.
While chickpeas are cooking, prepare dressing: stir all ingredients except olive oil together, then whisk continuously while slowly drizzling oil into the mixture. Set aside.
To assemble the salad, combine all ingredients, and gently toss with dressing.