Citizenship is largely irrelevant for tax purposes — under Irish law, whether your are liable to tax and how much tax you are liable for very rarely depends on your citizenship of Ireland or of any other country.
However if you have connections to another country — own property there, derive income from there, have or used to have residence there — then, yes, that can raise issues, and you are wise to be looking for advice. But it would probably be easier to give you a steer if you named the country concerned, and outlined the nature of your connection with it (other than being a citizen of it which, as I say, is largely irrelevant).