Warm Cauliflower and Herbed Barley Salad

Name: Warm Cauliflower and Herbed Barley Salad
Cuisine: Mediterranean, European
Ingredients: 1/2 cup pearled barley; Kosher salt; 1 tablespoon finely grated lemon zest; 3 tablespoons fresh lemon juice; 1 tablespoon mayonnaise; 1 teaspoon Dijon mustard; 6 tablespoons olive oil, divided; Freshly ground black pepper; 1 head cauliflower, cut into florets; 1 15-ounce can gigante, corona, or butter beans, rinsed; 1/2 cup flat-leaf parsley leaves, divided; 2 tablespoons fresh tarragon leaves, divided