1. In a large mixing bowl, combine the diced tomatoes, red pepper, and onion. Set aside to let the flavors begin to mingle.
2. In a separate small bowl, whisk together the garlic, allspice, vinegar, pomegranate molasses, olive oil, and about a third of a teaspoon of salt until the dressing is smooth and well blended. Pour it over the tomato mixture and toss gently to coat everything evenly.
3. Spoon the salad onto a wide serving platter, spreading it out slightly. Scatter the pomegranate seeds and oregano leaves over the top, and finish with a light drizzle of olive oil just before serving.