1. In a medium bowl, mix filling ingredients together, aside from grated cheese. Taste and adjust seasoning if necessary.
2. Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
3. Divide pizza dough into six equal parts. Roll each piece into a square. (Dough should be rolled to uniform thickness, to avoid holes during baking.)
4. Generously sprinkle grated cheese on one triangular half of the dough, leaving a one-inch (three centimeter) border. Spread the opposite triangular half with the tuna mixture, leaving the same border. Gently fold the tuna side over the cheese side. Press to close.
5. Use a fork to make marks all along the dough edges, pressing to seal. Continue until all dough and filling is finished. Brush with egg, and sprinkle with sesame seeds.
6. Bake for 12–15 minutes or until tops are golden and dough is baked through. Serve hot.
You can personalize your calzone! For a cheesier tuna melt, spread grated cheese on the entire square of dough before adding the tuna. For great flavor, thinly sliced onions can be added to one side. Other add-ins can be finely chopped red peppers, grilled sweet potato cubes, diced tomatoes, crushed garlic, and/or olives.