In a small mixing bowl, whisk together the lemon zest and juice, garlic, olive oil, salt and pepper. Set the dressing aside.
Combine the red bell pepper, cucumber, onion, chickpeas, olives, walnuts, mint, and parsley in a large mixing bowl.
Meanwhile, bring a large pot of water to a boil. Stir in 3 tablespoons of salt and a small splash of olive oil. Add the orzo and cook for 7 to 9 minutes, or according to the directions on the package. Drain the orzo in a colander, then add it to the vegetable mixture while the orzo is still hot. Immediately pour the dressing onto the orzo and vegetables, and stir to combine. The hot orzo will readily absorb the dressing.
Season with salt and pepper to taste. Add a splash more olive oil if the salad seems too dry. Allow the salad to cool to room temperature, and then add the feta. Cover and refrigerate for 1 to 2 hours. You can also make this the day before.