Oahu farmers markets, fruits & veggies?
Hope this post isn't too late. Kapiolani Community College at the base of Diamond Head has a great open market where they sell fruits, veggies and prepared foods and treats. Lots of free parking and you can go hiking in Diamond Head after checking out the open market! The open market is held Saturday mornings from about 8 to 11am. Go early to get the best selection. If you have a sweet tooth there are several bakery type items that you can't get at a store type location.
Aloha and enjoy!
There are a number of "open markets" sponsored by the city, usually at neighborhood parks in the morning hours.
Chinatown is another colorful place to check out, with the usual caveats about being aware of the people around you, and not venturing too far from the main streets.
There are also a number of restaurants in the area:
***Note that this is posted by a homesick Hawaiian (3 years in SoCal so far), so any listings may not be current.
Good luck, be careful, and enjoy. Aloha!