01 - Place eggs in a saucepan and cover with water. Bring to a boil over medium-high heat, then lower heat and simmer for 9–10 minutes. Transfer eggs to cold water to cool, then peel and chop.
02 - In a large mixing bowl, combine drained tuna, chopped eggs, diced avocado, celery, red onion, and chives.
03 - In a separate bowl, whisk together ranch dressing, Greek yogurt or mayonnaise, dill, lemon juice, salt, and black pepper until smooth.
04 - Pour the prepared dressing over the tuna mixture and gently fold until integrated, preserving the avocado texture.
05 - Taste and adjust seasoning. Chill for 10 minutes if preferred before serving in lettuce cups, as sandwich filling, or over toast.