1. Combine the ground cumin, garlic powder, ginger, allspice, 1/4 teaspoon of the salt and the black pepper in large plastic food-storage bag; seal and shake bag to mix ingredients. Open bag and add the pork cubes; seal and toss to coat the pork evenly.
2. Heat the vegetable oil in a large nonstick skillet over medium-high heat. When hot but not smoking, add the coated pork from the bag; stir-fry for 5 minutes or until the pork cubes are no longer pink in center.
3. Meanwhile, stir the broth into cornstarch in a small bowl until mixture is smooth. Add to skillet with pineapple and juice and remaining 1/4 teaspoon salt; cook, stirring, for 1 minute or until the mixture is thickened and heated through.
4. Stir the tomato into the hot rice in the saucepan in which the rice has been cooked. Spoon the rice mixture onto a serving platter. Serve the pork mixture over the rice.
5. Garnish the pork with the sliced green onion and chopped cilantro, if using. Makes 4 servings.