Heat oil in a saucepan over medium heat; add green onions and cook for 1 minute. Add barley and cook for 1 minute. Pour in chicken broth and bring to a boil. Reduce heat to medium-low; cover and cook for 30 minutes or until barley is tender and broth is completely absorbed.
Stir in tomatoes, olives, spearmint and lemon zest. To serve, sprinkle with feta cheese and pepper to taste. This dish goes beautifully with chicken or fish.