1. Bring 5 cups water to a boil in a large saucepan. Add farro and 1/4 teaspoon salt to boiling water; cook 15 minutes or until al dente. Drain; cool at room temperature 15 minutes. Combine farro, cherries, celery, walnuts, and parsley in a large bowl.
2. Combine lemon juice, mustard, honey, pepper, and remaining 1/4 teaspoon salt, stirring with a whisk. Gradually add oil, stirring constantly with a whisk. Pour dressing over farro mixture; toss to coat.