My favorite restaurant in Japan is El Boracho, only thing is, it's in Fukuoka, which is not in Tokyo. But here is a link to the restaurant, http://www.findinjp.com/restaurants/359/el-borracho-chuo.

Tokyo has like El torito which is a US mexican chain. But you should be able to find other mexican restaurants and things to do in Japan from this website, so check it out www.findinjp.com