Soften the Onion: Thinly slice the red onion and place it in a small bowl. Cover with cold water and stir in the lemon juice. Let it sit for 5 minutes to soften the flavor.
1 medium red onion, 1 tablespoon lemon juice
Prep the Beans: Drain and rinse the borlotti beans under cold water. Transfer them to a large mixing bowl.
3 cups canned borlotti beans
Assemble the Salad Base: Drain the onion and add it to the bowl with the beans. Drizzle in the olive oil and vinegar. Season with salt and pepper, then mix gently to combine.
4 tablespoons extra virgin olive oil, 2 tablespoons white wine vinegar, Salt, Black pepper
Add Tuna and Parsley: Flake the tuna into large chunks and add it to the bowl along with the chopped parsley. Toss everything together gently so the tuna stays a bit chunky.
2 5-ounce cans tuna in olive oil, drained, 2 tablespoons chopped fresh parsley
Serve or Chill: Serve right away or refrigerate for up to an hour if you want it colder. Tastes great with some crusty bread or a wedge of cheese on the side.