here's documents required for open work permit, all documents should be copies
- your work offer.
- your last 3 months payslips.
- your work permit.
- your taxes in canada.
- your passport + visa.
- bank account (last 3 months).
here's also another thread about your question
http://www.canadavisa.com/canada-immigration-discussion-board/spouse-open-work-permit-with-online-application-outside-canada-t150927.0.html