prepare the couscous
In a medium saucepan, toast the couscous over moderate heat, tossing, until golden, 10 minutes. Transfer to a small bowl. In the same saucepan, heat the olive oil. Add the onion and a pinch each of cinnamon and salt and cook over moderately low heat, stirring occasionally, until the onion is softened and just starting to brown, about 8 minutes. Add the toasted couscous and cook for 1 minute, stirring, then stir in the tomato puree. Add the warm water 1/2 cup at a time and stir constantly over moderately low heat, allowing the liquid to be absorbed between additions, until the couscous is al dente, about 20 minutes. Season with salt and keep warm; add 1 or 2 tablespoons of water if the couscous seems dry.