Coat the bottom of a large, deep skillet with olive oil, over medium-high heat. Wash and dry the chicken thighs, and season with salt and pepper on both sides. When oil is hot, sear them in the skillet, browning both sides. Remove the chicken and place on a plate—preserve all of the juices they release!
Reduce heat to medium and add the onion to the skillet, with the addition of more oil if necessary, and cook until slightly softened and browned—5 minutes. Stir in the ginger, garlic, chili powder, cumin, paprika, and turmeric.
Next, add the chicken pieces, and toss to coat in onion and spices—pour into the pan any juice from the plate the chicken was on.
Pour the chicken stock into the skillet, and nestle chicken into pan. Add the lemon slices and olives, and sprinkle the saffron. Bring stock to a simmer, cover the skillet, and simmer on medium-low heat for 10 minutes.
Transfer covered pan to the oven and cook for 7 minutes, then remove cover and cook for another 7 minutes.
When chicken is done, the onions and spices should be reduced to a thick paste. To serve, plate on top of wilted greens and leeks with fresh pepper. Enjoy!