All you need are either a Cedula (the I.D. card you receive once you have residency) or an R.N.C. number for a company, so that the tax people can come around and collect their portions of your revenues. Also, the Labor people have a way to collect their taxes on your employees, and know who to chase down if there's a beef with an ex-employee. (good luck)
Easiest way is to start a Dominican company with a low capitalization, like RD$10,000 and then start serving your food. Use a dominican lawyer , and ask a lot of questions through this process, and you will get an education.