Heat 1 tablespoon olive oil in a large pot over medium heat. Add the onion and sauté for 5–6 minutes until it softens. Add the sun-dried tomatoes and cook for 3–4 minutes, stirring occasionally. Add 1–2 teaspoons oil from the jar of sun-dried tomatoes if you like.
Stir in the garlic and cook for 1 minute until fragrant. Season lightly with salt.
Add the Castelvetrano olives, dry thyme, and chickpeas. Add a big pinch of crushed red pepper and toss to coat.
Simmer the soup:
Pour in the water or vegetable broth and bring to a boil. Reduce the heat and simmer, uncovered, for 15–30 minutes to let the flavors meld. Taste and add salt and pepper if needed.
Prepare the garnish:
Meanwhile, combine the lemon zest, minced parsley, olive oil, and a pinch of flaky sea salt in a bowl. Add the Aleppo pepper flakes and stir to combine. Taste and add more salt if needed. Set aside.
Finish the soup:
Return the soup to a boil. Stir in the orzo and boil for 7–9 minutes or until the orzo is al dente. Turn off the heat and stir in the lemon juice. Taste and adjust the seasonings one final time.
To serve:
Ladle the soup into bowls. Spoon the parsley garnish on top and enjoy!