To prepare the tapenade: Drain all but one tablespoon olive oil from the jar of Tonnino Tuna and then drain into the steel-bladed food processor container.
Add the anchovy paste, thyme, parsley, lemon peel and garlic and pulse several times. Add the lemon juice, 3 tablespoons olive oil and mascarpone and process until almost smooth.
Add the olives, capers and salt and pepper and pulse to mix.
Transfer the mixture into a container, cover with plastic wrap and refrigerate for at least 1 hour.
To prepare the crostini: Meanwhile, preheat the oven to 375° F. Brush one side of the bread lightly with olive oil. Arrange the bread on a baking pan and bake for 6-8 minutes. Allow to cool slightly.
Assembly: Spread the tapenade on each toast, sprinkle with parsley and serve.