How to Make It
Bring a medium pot of salted water to a boil. Stir in the rice and boil until just done, 10 to 12 minutes. Drain.
Meanwhile, in a large pot, heat the oil over moderately high heat. Add the pork, the scallion bulbs, the garlic, cayenne, and paprika and cook, stirring frequently, until the pork starts to brown, about 2 minutes.
Add the water, celery, zucchini, and salt. Bring to a boil. Reduce the heat and simmer, partially covered, until the vegetables and pork are tender, 15 to 20 minutes. Stir in the soy sauce, sesame oil, vinegar, tofu, and pepper and cook for 5 minutes more.
Stir the scallion tops into the soup. Put a mound of rice in the center of each of four bowls. Ladle the soup around the rice.