Prepare the Salad Base: In a large mixing bowl, combine the drained tuna, cannellini beans, and sliced red onion. Gently mix to combine, keeping some of the tuna chunks intact for texture.

Make the Dressing: In a small bowl, whisk together the olive oil, red wine vinegar, salt, and black pepper. Adjust seasoning to taste.

Combine and Add Herbs: Pour the dressing over the tuna and bean mixture and gently toss to coat all ingredients evenly. Add the chopped parsley (or your choice of fresh herbs) and mix gently to incorporate.

Present and Savor: Spoon the salad onto a serving platter or into individual bowls for a delightful presentation. Garnish with extra herbs if desired. Serve chilled or at room temperature, as a stand-alone meal or with crusty bread on the side.