1. Heat oil in a Dutch oven over high heat. Season chicken with salt and pepper and add to Dutch oven skin side down, working in two batches. Brown, about 5 minutes each side; transfer to a plate; and cover with aluminum foil.
2. Lower heat to medium and add fennel, ginger and garlic to same pot; cook until soft, about 5 minutes, stirring occasionally. Add Moroccan seasoning, olives, chickpeas, chicken with any juices that have accumulated, broth and lemon zest. Cover and simmer over low heat 45 minutes.
3. Meanwhile, pour 1 cups boiling water over couscous in a large heatproof bowl, stirring to combine. Cover with a dinner plate and let sit 10 minutes; fluff with a fork. Garnish chicken stew with pumpkin seeds, if desired, and serve with couscous.