Put onion and celery in a large skillet with about a tablespoon of olive oil and a pinch of salt. Cook over medium heat until onion is translucent. Stir in the garlic and cook for about a minute before adding the tomato, lemon, sundried tomatoes, olives, and apricots. Mix well, then stir in the tomato paste, chicken stock, brown sugar, and paprika. Bring mixture to a boil, then add the chicken thighs. Lower heat to a simmer and cover pan. Simmer for 45 minutes to an hour, until sauce has reduced and thickened and chicken is very tender.
Serve with your favorite starch. (I used black rice.)