Coat the bottom of a soup pot with oil. Over medium heat, brown the chicken. Add leeks, red pepper and mushrooms and saute for 5 minutes until soft. Add coconut milk and broth. Bring to a boil, reduce heat and simmer for 15 minutes.
Add tofu (optional), spinach, cilantro, and lime juice and heat until greens are just wilted. Add salt, pepper and hot sauce to taste.