AFAIK, Hare krishnas do not practice "raja yoga" the Hindu school of philosophy that deals with "Yoga" and "meditation" as people know of it popularly. Hare krishnas practice the "Bhakti" (devotional) school of philosophy.

Zen meditation is a japanese adaptation of the chinese adapation of the Raja Yoga techniques of Hinduism/Buddhism.

see http://en.wikipedia.org/wiki/Raja_Yoga