1. Heat oil in a large heavy pot over medium heat. Add sausage, and cook about 5 minutes. Add onion and garlic; sauté 5 minutes. Add 3/4 teaspoon salt and next 7 ingredients; stir well. Add stock, and bring to a boil; reduce heat, and simmer 20 minutes or until pumpkin is tender when pierced with a fork. Stir in zucchini and chickpeas; simmer about 10 minutes more or until zucchini is tender but not falling apart.
2. Cook couscous according to package directions with remaining 3/4 teaspoon salt. Fluff with a fork; keep warm until ready to serve.
3. Pile warm couscous on a large platter. Remove sausage and vegetables from pot with slotted spoon, and place around couscous. Garnish, if desired. Pour broth into a serving bowl. Invite guests to serve themselves individual portions of couscous, vegetables, and broth.
*Substitute 1 butternut squash or large sweet potato, if desired.