01 - Rinse pearl barley under cold running water. Combine barley, 3 cups water, and 1/2 teaspoon salt in a medium saucepan. Bring to a rolling boil over high heat, then reduce to low, cover, and simmer for 25 to 30 minutes until grains are tender yet retain a pleasant chew. Drain any remaining liquid and spread barley on a sheet pan to cool to room temperature.
02 - While the barley simmers, dice the English cucumber into small cubes, finely chop the red onion, halve the cherry tomatoes if using, and roughly chop the parsley, mint, and dill. Set aside.
03 - In a large mixing bowl, whisk together the extra-virgin olive oil, freshly squeezed lemon juice, orange juice, lemon zest, orange zest, honey or maple syrup, minced garlic, black pepper, and a pinch of salt until the dressing is emulsified and smooth.
04 - Add the cooled barley, diced cucumber, red onion, cherry tomatoes, parsley, mint, and dill to the vinaigrette. Toss gently with a large spoon or tongs until every ingredient is evenly coated with dressing.
05 - Taste the salad and adjust salt and pepper as needed. Serve chilled or at room temperature as a light main or a vibrant side dish.