Tuna & Tomatoes Provencale

1/2 teaspoon kosher salt

2 tablespoons extra-virgin olive oil

2 tablespoons balsamic, or red-wine vinegar

2 tablespoons lemon juice

1/2 teaspoon freshly ground pepper

2 6-ounce cans chunk light tuna, drained and flaked (see Note)

1/2 cup diced roasted red peppers

1/4 cup chopped pitted black olives

1/4 cup chopped fresh basil

1/4 cup chopped fresh chives, or scallion greens

2 tablespoons drained capers

4 large vine-ripened tomatoes Several fresh basil leaves for garnish