The only place to eat near the ferry landing on Orcas Island is the Boardwalk restaurant http://www.orcasislandboardwalk.com/.  The rest of the restaurants on Orcas Island are located several miles away.

The same goes for Lopez; there are no dining establishments at the Lopez Island ferry landing.

So that leaves Friday Harbor on San Juan Island; here you have multiple dining choices within walking distance of the ferry landing .
http://www.downriggerssanjuan.com/
http://www.maloula.com/
these places might only be open for dinner:
http://www.theplacesanjuan.com/
http://www.stepswinebarandcafe.com/
http://www.ducksoupinn.com/

Ferry schedule: http://www.wsdot.wa.gov/ferries/

Thanks for posting on the islands message board and enjoy your trip to the San Juan Islands.