In a medium bowl, combine the drained tuna, whole wheat breadcrumbs, beaten egg, Greek yogurt, green onion, Dijon mustard, lemon juice, dill, salt, and pepper. Mix well until all ingredients are fully incorporated.
5 oz tuna, 2 tbsp breadcrumbs, 1 egg, 1 tbsp Greek yogurt, 1 tbsp green onion, 1 tsp Dijon mustard, 1 tsp lemon juice, 1 tbsp dill, ⅛ tsp salt, 1 pinch pepper