On a recent trip, a tour guide mentioned that the Polynesian people may have their origin in the fertile crescent. He said their language, religion, and genetic profile were similar. He then went on to claim that they could be a long lost tribe of Israel. Is there any truth to what he said?
I suspect you were at a Mormon/Polynesian interpretative center. There is no basis for believing that Polynesians were from the fertile crescent or are in any way associated with a lost tribe of Israel. This was something Mormon's advanced to suit their church's contrived vision of the past and the dispersal of the Jewish people. Recent DNA analysis demonstrates clearly that Polynesians (and Native Americans - something else Mormon's advanced) have no such origin - but of course, there was never any real documentary or archaeological evidence to suggest this was the case.
The answer is no.
Linguistically, classical Hebrew is part of the Semitic branch of the Afro-Asiatic languages. It has nothing to do whatsoever with the Austronesian language family of which the Polynesian languages are a part.
In terms of religion, it is possible that missionaries spread Judaeo-Christian ideas to Polynesia, and that these ideas were incorporated into the religion of the peoples there. Before that contact, however, similarities in religious practice (including ritual and stories) must be coincidental considering the enormous amount of distance between the western Levant and Polynesia.
Though this wasn't part of your question, some additional remarks on the 'lost tribes of Israel'. The conquest of the country of Israel (not Judah, whose elite would write the texts that subsequently became the canon of the Hebrew Bible) by Shalmaneser V of Assyria led to an extensive resettlement programme, under which most of the population was moved to other parts of the Assyrian Empire.^1 According to the Hebrew Bible, Israel was home to ten of the twelve tribes chosen by Yahweh (whether this has any historical basis is another question, but carefully speaking the answer is 'probably not in that form'.). Because of the resettlement policy, the members of those tribes were thus 'lost' - but the Hebrew Bible never really makes much of it. The books of Ezra and Nehemiah focus almost exclusively on Judah and Jerusalem, and we don't have any other contemporary sources that discuss the matter in terms of identifying the lost tribes.
It's not until Christianity comes along that the lost tribes become an incredibly useful hook to claim 'chosenness', and even then it takes until the 17th century or so for the idea really to become a big deal.^2 You can easily see Mormonism in the same vein, of course, and in many ways it was a product of its time.
^1 Cogan, M. Imperialism and Religion: Assyria, Judah, and Israel in the Eighth and Seventh Centuries BCE, Scholars Press (1974).
^2 Parfitt, T. The Lost Tribes of Israel: The History of a Myth, Weidenfeld and Nicholson, 2002.