Cut chicken into small cubes and cook until almost done. In a separate pan, combine water and paste and bring to a boil. In another pan, combine chopped onion and cilantro and blend, 1/3 cup broth for each cup of vegetables. Mix flour with the broth and addrest of broth and pureed vegetables. Add all other ingredients except the evaporated milk and boil. Reduce temperature and add milk. Heat through, but do not boil.