Drain the beans and transfer them to a pot. Add enough water to cover them by 2 inches. Bring to a boil, reduce the heat, and simmer the beans for 1 1/2 hours. Drain them and set them aside.
In a flameproof casserole, brown the beef over medium-high heat, stirring, until the meat loses its pink color. Transfer the meat to a bowl.
Wipe out the pan. Add the oil and heat it. Add the onions and cook over medium heat for 10 minutes, stirring often. Stir in the garlic and cook for 1 minute.
Return the meat to the pan. Add the tomatoes and their liquid, the dried pepper, water, chili powder, oregano, cumin, salt, and black pepper. Bring to a boil, lower the heat, and cover the pan. Simmer the chili for 1 hour.
Add the beans and continue cooking for 1 hour. If the mixture seems dry, add more water.
Taste the chili and add more salt and pepper if you like. Serve at once, sprinkled with the Cheddar cheese and scallions.