Bring water to a boil in a saucepan. Stir in couscous, return to a boil, cover and turn off heat. Let sit (without lifting the lid) until the water has been absorbed. Meanwhile, stir together tahini and orange juice to make a smooth paste. Place yogurt or tofu in a large mixing bowl and whisk until light and smooth. Whisk in tahii mixture, cumin and ginger. Stir in chickpeas, mango and raisins. Fluff couscous with a fork to break up any lumps. Stir into mago mixture. Add cilantro and dried fruits if desired; stir until thoroughly blended. Cover and refrigerate until chilled through, aout 3 hours. Serves 4 as a side dish. Per serving (lacto version): 246 cal; 10 g prot; 2 g fat; 47 g carb; 1 mg chol; 611 mg sod; 6 g fiber Vegetarian Times, August 1993/MM by DEEANNE