The one spot that I recommend to everyone visiting Kauai is: PONO MARKET.
4-1300 Kuhio Hwy
Absolute local food heaven. Personally, I would skip out on all the touristy restaurants and hit this place up every day. I say this because they have so many different kinds of dishes and different specials every day, that I couldn’t possibly tire of it for at least a week (when the menu cycles). :)
Do yourself a favor. Make Pono a stop on your first day if you’re down for the indigenous experience, and let it set the tone for the culinary portion of your trip.
On another note, you’ll probably hear much about HAMURA SAIMIN, and I’m sure the place had its heyday, but keep your expectations low if you decide to partake. Their broth is great and I’m “guessing” that their noodles might also be great, but I wouldn’t know because they were cooked way past al dente each time I’ve been. Personally, I feel that overcooked noodles are the worst thing you can do to a bowl of saimin (or ramen). You might want to see if you can make a special request for “harder noodles” for insurance; always better to have harder noodles which can continue to cook in the broth than to have soft noodles beyond repair. In addition, I’ve never seen the owners on my trips there which might explain the lack of quality cooking.
Finally, if I had to pick a touristy spot to eat, I would go with THE BEACH HOUSE RESTAURANT in Koloa. Make a reservation at about an hour before dusk and request a table at the window. The sunset is absolutely beautiful and the food is pretty good too. If you're in the Princeville area, the CAFE HANALEI patio has spectacular views of Hanalei Bay and Bali Hai.
My husband and I just returned from Kauai and thought the island was fantastic and the food was TERRIBLE. Everyone told us that we HAD to go to certain places and then when we did, they were mediocre at best. We will return to the island, but next time we will pack an entire suitcase of dry and canned goods to get a headstart on the outrageous grocery prices there and we will cook in the condo. Now we know why the CostCo was so crowded. Here's where we DID eat:
BARACUDA in Hanalei- extremely expensive, very average at best.
POSTCARD in Hanalei - one of the better meals, but that's just better compared to all the rest which were bad.
ONO BURGER - near Kapaa- surely nothing fancy, but one of the BEST meals we had on the island. Way better than Bubba burgers by far.
KEOKI'S - in Poipu - Think Fridays or Bennigans.
CHINESE - the counter place everyone talks about in the China Village in Hanalei was our best meal next to Ono Burger.
Down in the southern part of Kauai you can find really good restaurants and all the hotels have bars with great views and some music. Keoki's Paradise offers lots of tropical fare and music nearly every night. Duke's is always a fun place with decent food. Have a great time and try to get up to the north part of Kauai. You will be amazed!