Combine the ground beef with the cilantro, garlic, lime juice, cumin, hot sauce and salt and pepper. Form into 1-ounce balls. Heat oil in skillet over moderate heat. Cook until brown on all sides, about 5 minutes.
In a large soup pot, heat 2 tablespoon vegetable oil. Add onions and garlic and cook for 5 minutes over low heat until translucent. Add chiles and cook 2 minutes. Add tomatoes and their juice, chicken stock, chili powder, cumin, and hot sauce. Simmer for 15 to 20 minutes.
In a small bowl, combine flour and chicken stock. Whisk into soup. Bring back to a boil. Reduce heat and simmer for 5 minutes. Add meat balls and simmer an additional 5 minutes.