In a large heavy pot heat oil over medium high heat. Stir in the onion and cook for 3 minutes or until tender. Stir in spices and cook until aroma is released. Stir in carrots, potatoes and squash and toss to coat. Cook vegetables for 5 minutes. Stir in tomatoes and water. If necessary add enough water so that all the vegetables are submerged. Bring to a simmer and cook for 20 minutes. Stir in zucchini and continue to cook for 20 more minutes. Stir in the chickpeas and season with salt and pepper, Tabasco and cilantro. Serve hot with couscous and warm pita bread.