Cut the onion in half and slice one half into half rings. Dice the other half.
Heat 1 tablespoon oil in a frying pan over medium heat and fry the chicken on all sides until no longer pink in the middle. Season with salt and pepper and set aside.
Place the diced onion in the frying pan and cook, stirring, until soft. Add ginger and garlic and fry a few minutes until fragrant.
Add cumin and cinnamon and stir well. Add tomatoes and their juice and bring to the boil. Turn down the heat and simmer over low temperature at least 10 minutes.
Meanwhile, heat the remaining tablespoon oil in a small saucepan and fry the sliced onion until soft. Add couscous and chicken stock, bring to the boil and remove from the heat. Cover and let sit 5 minutes, until stock is absorbed.
Return the chicken meat to the simmering tomatoes. Add chickpeas, stir and heat through. Season with salt and pepper to taste.
As soon as the couscous is ready, stir in capers and pine nuts. Serve with the chicken.