In a large saucepan, heat oil over medium-high heat. Sauté the onion for about 5 minutes, until soft. Add garlic and ginger and cook for another minute. Add the paprika, salt, pepper, cumin, turmeric and chile flakes and cook for another minute.
Add the tomatoes and then a full can of water (use the tomato can), the lemon juice, squash, carrots and chick peas. Bring to a simmer, reduce heat to medium-low, cover and simmer for about 30 minutes, until the vegetables are tender.
Stir in the raisins, taste and season with salt and pepper. At this point you can cool it completely and refrigerate for a day or two, to allow the flavors to meld; rewarm on the stovetop or in the microwave. To make the couscous, put it in a bowl and pour 1 1/4 cups boiling water overtop; cover with a plate and let sit for 10 minutes. Fluff with a fork.
Serve hot over couscous (or rice or quinoa), topped with a dollop of yogurt and a sprinkle of chopped cilantro or toasted almonds.