Which island and what elevation? Just on the Island of Hawaii (the Big Island) it's got something like eleven of the possible what is it, thirteen climate zones on the planet?

Depending on her location and elevation, along with rainfall, some things will grow really well and other things won't.

Assuming she's somewhere on Oahu, she could try cherry tomatoes. Those do pretty well and the fruit flies leave them alone. It's the middle of summer now, so the red lettuces, buttercrunch and the romaine lettuces grow now. Later on, during the cooler winter months, she can grow Manoa lettuce and green leaf lettuces. Green beans should go well.

Here's a source for Hawaii seeds: http://www.ctahr.hawaii.edu/seed/seeds.asp They are the U of H at Manoa seed program and they have home gardening packets for inexpensive.

Thank you for the recommendations! I forgot to mention she lives at Kailua Beach (elevation 0 or close to it) on Oahu.