Warm Cauliflower and Herbed Barley Salad

INGREDIENTS

• 1/2 pearled barley
• Kosher salt
• 1 finely grated lemon zest
• 3 fresh lemon juice
• 1 mayonnaise
• 1 Dijon mustard
• 6 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 flat-leaf parsley leaves, divided
• 2 fresh tarragon leaves, divided