1. Rinse the barley under cold water.
2. In a pot, bring the water to a boil. Add the barley, reduce heat, and simmer for 30 minutes or until tender.
3. Drain the barley and let it cool.
4. In a large mixing bowl, combine the cooled barley, cherry tomatoes, cucumber, red onion, and parsley.
5. In a small bowl, whisk together the olive oil, lemon juice, salt, and black pepper.
6. Pour the dressing over the salad and toss to combine.
7. Serve chilled or at room temperature.