The Hawaiian equivalent of the English phrase "trick or treat" is kiliki o lapu (which literally means treat or else (be) haunted).
Use this Hawaiian language dictionary to find out how English terms are translated to Hawaiian words.
Hawaiian is closely related to the other major Polynesian dialects: Tahitian, Maori, Marquesan, Rarotongan, Samoan and Tongan. Although it is not necessarily mutually intelligible with these other dialects, many Hawaiian words and grammatical concepts are identical or nearly identical with the other dialects. Learn more at here.
Of interest, Honolulu Magazine shares the best events in Hawaii where you can go trick-or-treating with your family.