Ingredients

• 2 cans light tuna in olive oil, drained and broken in pieces
• 1 stalk celery , finely diced
• 1/4 cup mayonnaise
• 1/4 cup 2% plain Greek yogurt
• 1 teaspoon Dijon mustard
• 1 teaspoon lemon juice
• 3 tablespoons fresh flat-leaf parsley , finely chopped
• 3 tablespoons fresh oregano , finely chopped
• 2 tablespoons fresh chives , finely chopped
• salt and pepper
• 4 submarine sandwich buns , halved horizontally
• small leaf lettuce or boston lettuce
• 1/2 cup microgreens (optional)