Preheat the broiler and line a baking sheet with foil. Pat the pork dry, brush with 1 tablespoon olive oil and season with salt and pepper. Toss half each of the scallions, parsley and dill in a small bowl; rub all over the pork. Transfer to the baking sheet and set aside.
Heat the remaining 1 tablespoon olive oil in a large Dutch oven or pot over medium-high heat. Add the remaining scallions, the celery, garlic and rice. Cook, stirring, until the vegetables are tender, about 2 minutes. Add the tomatoes, 2 cups water and 1 teaspoon salt. Bring to a boil, then reduce the heat to medium low; cover and gently simmer until the rice is tender, about 20 minutes.
Meanwhile, broil the pork, turning once, until lightly browned and a thermometer inserted into the center registers 145 degrees F, 16 to 20 minutes. Let rest 5 minutes.
Stir the parmesan and remaining parsley and dill into the rice; season with salt and pepper. Slice the pork and serve with the rice. Top with more parmesan and parsley.