Rinse farro under cold water in a strainer, and set aside until needed.
Add oil, ground beef, and salt to a pan set over high heat. As beef starts to brown, break into small crumbles with a spatula. Add mushrooms and cook, stirring, until mushrooms and beef are as browned as you like, about 5 minutes. The browner the better. You can reduce the heat to medium-high if the pan seems to be getting too hot.
Add onions and celery and cook, stirring, until onions start to turn translucent, about 3 minutes. Season with black pepper, cumin, paprika, garlic powder, and oregano, and cook, stirring, for 1 minute. Stir in tomato paste, and cook for 1 to 2 more minutes.
Add farro to the pan, and stir until coated with olive oil and rendered beef fat. Pour in beef broth, and stir to combine. Raise heat to high, and bring pan to a simmer. Stir again, cover the pan tightly, reduce heat to medium-low, and cook for 10 minutes.
After 10 minutes, uncover and test the farro for doneness. It should have the texture of al dente pasta. Turn off the heat, cover, and let rest for 7 minutes. Uncover, and stir in chives and Cheddar cheese. Taste for seasoning, and adjust if needed. Serve immediately.
