Favas take work (the younger ones, with thinner pods, are the most difficult), but these basic techniques help make the task manageable.
1. Pinch off stem and pull away string along seam of pod.
2. Run your thumbnail down seam, pry shell open, and remove beans.
3. To slip beans out of their skins, blanch them for 30 seconds or so, cool them in cold water, hold bean on grooved side, and pinch to slip out bean.