Garden Tuna Salad Sandwich

• 15 oz. solid light canned tuna, drained
• 1/2 cup chopped fennel
• 1/2 Granny Smith apple, cored and chopped
• 1/3 cup mayonnaise
• 1 Tbsp. lemon juice
• 1 1/2 tsp. fennel seeds
• 1 tsp. ground coriander
• 1 tsp. lemon zest
• 1/2 tsp. sea salt
• 6 split hot dog rolls
• 6 Boston lettuce leaves

For Parsley Vinaigrette

• 1/2 large lemon, juiced
• 1 cup chopped flat-leaf parsley
• 1 Tbsp. honey
• 1/4 cup light oil (grapeseed or safflower)