In a large plastic bag, combine flour and fajita seasoning; add chicken. Seal bag and shake to coat.
In a large saucepan, saute chicken in oil until no longer pink.
Add the onion and saute until onion is tender; add garlic, cook 1 minute longer.
Add water and soup to a 5-6 qt. slow cooker stir until blended.
Add chicken mixture and all remaining ingredients (except cilantro) to slow cooker.
Cook for 4 hours on high.
Garnish with cilantro