Bring the stock, 1 1/4 cups water, oil, lemon zest, cumin and a pinch of salt to the boil in a large saucepan. Add the couscous, return to the boil, then remove from the heat, cover and stand for 5 minutes.
Place a large, heavy bottomed pot over medium heat. Stir in the cumin, ginger, cloves, cayenne, cardamom, coriander, and allspice; gently toast until fragrant, about 2 to 3 minutes. Stir in oil and onion, cook until softened. Stir in the capsicum, and zucchini; cook for 5 minutes. Stir in the raisins, salt, zest, and chickpeas.
Pour in the chicken stock and orange juice; turn heat to high and bring to a boil. When the mixture is boiling, stir in the couscous and remove from heat; cover, and let stand 5 minutes. Fluff with a fork and fold in chopped mint.