Following is from this valuable site Take a look and get their free guide to working in the Dominican Republic.

Working in the Dominican Republic
Anyone intending to do business or work in the Dominican Republic will need to acquire a residency permit in order to do so legally. There are several advantages to doing so apart from the obvious one of not being subject to deportation by immigration authorities. For one thing, legal residents are allowed to bring household goods (including computers, printers and other equipment that may be needed in the course of working) into the country duty-free.

There are also income and other tax exemptions available to legal residents. Also, in order for Dominican-earned income to be excluded from your U.S. income tax obligations under the Foreign Earned Income Exclusion, you must be a legal resident of a country other than the United States and having official residency goes a long way toward establishing your status as such under the bona fide residency test.

Obtaining residency in the Dominican Republic is a relatively straightforward process but requires a significant amount of paperwork. Applicants should consider applying for a temporary or provisional residence visa from a Dominican consulate abroad and then apply for a permanent residence permit with the Department of Migration in the country within 60 days of arriving.

The provisional permit is valid for one year. After one year as a provisional resident, eligible applicants may apply for permanent residency. You’ll resubmit much of the same documentation as you did for the provisional card, plus sworn statements by two people who attest to knowing you in the Dominican Republic and that you’re a law-abiding person. The permanent residency permit is valid for two years. After two years of holding the permanent residency permit, you may apply for Dominican citizenship.