In a large mixing bowl, combine the flaked tuna and drained white beans.
5 oz tuna, ½ cup white beans
Add the chopped cucumber, halved cherry tomatoes, sliced red onion, and Kalamata olives. Toss gently to combine.
¾ cup cucumber, ½ cup cherry tomatoes, ¼ cup red onion, 2 tbsp Kalamata olives
In a small bowl, whisk together the olive oil, lemon juice, red wine vinegar, dried oregano, salt, and pepper.
1 tbsp olive oil, 2 tbsp lemon juice, 1 tsp red wine vinegar, ½ tsp dried oregano, 1 pinch salt, 1 pinch pepper
Pour the dressing over the salad and toss until everything is evenly coated.
Sprinkle the crumbled feta cheese (if using) and chopped fresh parsley or dill over the salad.
2 tbsp feta cheese
Let the salad sit for 5–10 minutes to allow the flavors to meld, or serve immediately.