In a 12 inch non-stick skillet heat oil over medium heat. Add potatoes and cover for five minutes. Stir and toss with a wooden spoon, add diced bell peppers, and sliced green onions cover for 5 more minutes. Stir well and uncover. Cook for 5 more minutes tossing every few minutes. Add broth, sumac and zatar and heat well while tossing and scraping pan. Top with freshly chopped cilantro when serving on hot plates.