Place an oven rack in the center of the oven. Preheat the oven to 400 degrees F. Dust a baking sheet with cornmeal. Set aside.
For the tapenade: Place the olives, lemon juice, oil, capers, rosemary, thyme, anchovies and garlic in a food processor. Blend until smooth.
On a lightly floured work surface, roll out the pizza dough into two 10-inch diameter circles, each about 1/4-inch thick. Using a 4-inch round cookie cutter, cut out 4 circles of dough from each and transfer to the prepared baking sheet. Using the tines of a fork, prick the dough all over. Spread about 1 tablespoon of the tapenade over each dough circle (any extra can be used to top fish or chicken, or mixed through pasta or used as a spread for sandwiches) and place a slice of tomato on top. Drizzle with olive oil and bake until the dough is crisp and golden, 15 to 20 minutes.
Place the tuna and the olive oil from the tuna can in a small bowl. Using a fork, lightly mash the tuna. Divide the tuna and spoon on top of the cooked dough. Arrange 3 pieces of green bean on top of the tuna and serve.
To blanch the string beans, place in a medium small sauce pan of boiling water for 1 minute until bright green and crisp-tender. Drain and place in iced water to cool.