Preheat oven to 400o F. Heat 1 tablespoon oil on medium-high heat. Add chicken legs and cook about 3 minutes a side or until golden. Season with salt and pepper. Place in baking dish and bake for 20 minutes or until juices are clear.
Meanwhile soak chilies in boiling water for 30 minutes. Drain, stem and seed them. Place in food processor or blender.
To make mole sauce, heat 2 tablespoon oil in skillet on high heat. Add onions and garlic and fry about 1 minute or until onions are slightly browned. Add sesame seeds and cumin and cook 1 minute longer. Combine with chilies in processor. Stir tomatoes into skillet and cook until slightly browned at edges 3 minutes. Scrape into food processor along with oregano, cinnamon, raisins, chocolate and stock. Process until smooth.
Add remaining 1 tablespoon oil to skillet on medium-high heat. Place contents of processor in skillet, bring to boil, reduce heat and simmer for 30 minutes. Season with salt and pepper. Reserve.
Add chicken into skillet and heat together until chicken is hot. Place chicken on serving dish. Coat with sauce and sprinkle with coriander.