1. Prepare the Ingredients:

Start by draining the canned tuna and using a fork to flake it into small pieces. This will make it easier to incorporate into the salad. Wash and chop all the vegetables: halve the cherry tomatoes, dice the cucumber, thinly slice the red onion, and slice the Kalamata olives.

2. Combine the Salad Base:

In a large mixing bowl, add the flaked tuna, cherry tomatoes, cucumber, red onion, Kalamata olives, feta cheese, capers, parsley, and basil (if using). Gently toss the ingredients to distribute them evenly.

3. Make the Dressing:

In a small bowl or jar, whisk together the lemon juice, olive oil, dried oregano, salt, and black pepper. If you’re adding Dijon mustard for extra flavor, whisk it in at this step. Taste and adjust the seasoning as needed.

4. Toss the Salad:

Pour the dressing over the tuna and vegetable mixture. Gently toss to coat all the ingredients in the dressing without breaking the delicate pieces of tuna.

5. Taste and Adjust:

Taste the salad and adjust the seasoning as needed. Add more lemon juice for tang, olive oil for richness, or salt and pepper to enhance the flavors.

6. Serve:

Transfer the salad to a serving dish or individual bowls. Garnish with extra parsley or a sprinkle of feta cheese, if desired. Serve immediately, or refrigerate for 30 minutes to allow the flavors to meld.