Most listings are in the $0's per square foot per year. The Kauai County region is going through a decrease in rates. In the last 3 months, the median rate fell $15 per sqft per year. That's a 100% decrease in rent.
In the last 90 days, 5 listings have come on the market, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around sqft. Most buildings in this market were built in 1987 and are Class A.