To establish a constitutional claim of excessive force und the 4th amendment you must show that the police officer used unreasonable force. Factors to be considered include the nature of the crime, any resistance to the arrest, any effort to flee and the like. These cases depend on the facts. Having said that using a taser on a handcuffed prisoner could be excessive force. Being tased without a warning could also be excessive force unless the police had a reason to use force without a warning, typically the reason would be that the police officer thought you were armed and dangerous so they had to surprise you. You should contact a civil rights lawyer in Washington to evaluate your case since it depends on evaluating the facts in the police reports as well as from you and the witnesses.