Grocery Stores:
Cultimara in downtown Kralendijk is the place to go. It's more European that US/Canadian, so if you have no experience outside the US, be prepared for a fairly high weirdness factor - but this is supposed to be something of an adventure, isn't it? Prices are higher than you're probably used to, since just about everything has to be imported, but not crazy. Almost everything you can buy in the US/Canada is there, just different. There is seafood (fresh, good, varied) and beef (South American, close runner up to American quality and way better than you can find in Europe) and chicken, along with lots of sausages and cheeses. Don't eat the donkeys or flamingos. Portions are packed smaller than the US - the locals just don't eat a quarter pound of meat at every meal. Fruits and vegetables are plentiful. The island water is all manufactured, so you won't have any gastro-prblems with it. When you get into the prepared foods, a working knowledge of Dutch will be helpful in reading labels - that's where most of it comes from. Critical food items for fussy eaters? Consider bringing them along. You can get Vegemite for instance, but peanut butter is almost unheard of.
Restaurants:
There's a bunch of good to very good restaurants, nothing great. Most of the hotels have restaurants that are adequate, but not much above that. Richard's, Mona Lisa, Capriccio's and Fishes are my favorites of the non-resort "upscaleish" operations, all in the Kralendijk vicinity. Have a beer (or 10) at Karol's on the quay in downtown Kralendijk and something casual at Zee Zicht across the street. Find out if you like Dutch standards like kroketten and fricandellen. There's a nice little ice cream store a few doors south, too! If you must, KFC is even available. Plenty of everything in every price range except 5-star.
I'd say you may be over-thinking this. Nobody goes to Bonaire because of the food and nobody refuses to back because of the food, either. The island sees thousands of NorteAmericanos every year and they've pretty much learned to give us the coddling we seem to want. Relax, enjoy the laid back casual and if you ask, the local can clue you in on some of the spots that don't cater to tourists. That's where the fun can really start.
Bon voyage!
Steven
So I'm getting what info I can, Bonaire looks like a blast to dive, and this is my #1 reason for wanting to go, the others are divers as well, they'll forget all their cares once they get there 
