Since Hawaii is a part of the U.S., you will find the same Kosher signs here as you would in your own supermarket at home.
You can also buy Kosher products from the following stores on Maui, Hawaii:
COSTCO (Kahului): Sabra Chumus, Lox, Rye Bread and many more Kosher products (You will get the best value for your $ at Costco)
SAFEWAY (Kahului, Kihei, Wailuku): Small Kosher Section
WHOLEFOODS (Kahului) Huge selection of Kosher Products
MANA FOODS (Health Food Store in Paia): A HUGE variety of Kosher Pareve Products, Great Prices and Worth the Trip