Cook the quinoa in a rice cooker, or on the stove top as per package instructions.
Spread the cooked quinoa in a wide salad bowl to cool.
Meanwhile, chop the cucumber, red pepper, green pepper, and onion into small bite sized pieces, about 1/2” thick. Just make sure all the veggies are the same size.
Once the quinoa has cooled to room temperature, lightly fluff it up with a fork.
Add the chopped veggies, preserved lemon (if using), chickpeas, and Za’atar to the quinoa and mix together.
Next, add the juice of half a lemon, salt, crushed black pepper, and the chopped herbs (reserve some herbs for garnish) and toss together.
Add the arugula and cheese and mix gently, reserving some cheese for garnish.
Taste the salad and adjust the seasoning and acidity.
Chill for half an hour before serving garnished with the remaining cheese and herbs.