Easy Way To Flush Out A Converter?

Buy a reman converter. Unless you take your converter to someone who not only can cut it open, has the ability to assemble it and weld it up properly then check it out for proper converter hub runout (ie a converter rebuilder) you're taking a big chance. Others have suggested just flushing it out in some manner. Having seen many converters cut open there is material (clutch plates etc) that can compact on the outer edges of the vanes on the pump side of the converter that cannot be removed by just flushing the converter.
You've got a fresh transmission, so why take the chance on the converter.