Prepare Salsa Verde: In a small bowl, combine chopped fresh parsley, basil, drained capers, minced garlic, anchovy paste (if using), red pepper flakes, and pepper. Slowly drizzle in olive oil while whisking until smooth, then mix in red wine vinegar.

Combine Salad Ingredients: In a mixing bowl, add rinsed cannellini beans, halved cherry tomatoes, torn green olives, and sliced red onion. Sprinkle with kosher salt and toss gently to mix.

Dress the Salad: Drizzle the prepared salsa verde over the salad and toss carefully to coat everything without breaking delicate ingredients.

Finish and Serve: Top with parmesan shavings and optional tuna. Serve fresh with crusty bread for a satisfying meal.