No problem for residents
My wife and I have been living in the DR since 1986, mostly in Samana, but we purchased a condo Sosua and have been living here for about two years. Only for a very brief time in either place were we bothered by vendors. If you act like a resident instead of a tourist, they quickly get to know you and leave you alone. For example, since we moved to Sosua we have been taking walks along the beach--good exercise and plenty of shade. I am almost never approached by a vendor, they look past me toward any tourists that are in sight.
Some recommendations:
1. Don't go into the tourist shops or look at the jewelry, etc., being sold on the street. If you act like a potential customer, then they are going to go after your business.
2. When walking somewhere, act like you are going somewhere. If you are stopped, do #4 & #5. Do not get upset, do not berate the vendor, etc.
3. Don't dress and look like a tourist (no bathing suits or short shorts on the street, for example). Look like a solid citizen. When you are here, look around. It won't take you long to see what are tourists and which are residents.
4. When approached by a vendor, just keep walking. Wave an index finger back and forth, it is the Dominican signal for "no" or "not interested". You can do same if a taxi, guagua, or any other individual or service tries to attract your attention to something you aren't interested in.
5. In addition to #2, when someone comes up to you, say something like "yo vivo aqui" (I live here) or "vivimos aqui" (We live here)
If you act like a resident, I guarantee you that--except for a short getting-acquainted period--you will have no trouble with vendors. You will still get an occasional question or offer, but it will be respectful and the person won't be surprised by your response.
Enjoy your retirement. A lot of us are, and vendors are the least of our problems.