Wander into any bookstore in Okinawa and you will see a variety of local guides to food (not paid ads!). These guides are typically less than 1000円 (10 USD). Although they are in Japanese, they are great resources; simply look at the pictures for each place and whatever looks good, find it on the map insert, or better yet put the phone number into google maps. Easy-peasy. Pretty much every place I have tried from these books is pretty good.