[Wasabista]

In Vancouver there are a number of mining companies and they have a strong need for Spanish language ability, along with Portuguese, because they do a lot of business in Latin America.

In Japan the interest would mostly be from individuals who want to travel to Spanish speaking places. It's a bit of an area of specialization compared with English, however, so I would advise staying in Tokyo or Osaka.

Also bear in mind that a large number of ethnic Japanese have succeeded in obtaining long-term residence in Japan. That's your competition. So it might not be as easy as it used to be.