You have several issues;
1. Residency. When you leave the country you must notify the Revenue that you are doing so. This has two advantages;
a) you will get a refund on any tax overpayments for the year you leave
b) you are setting yourself up for losing residency
2. PAYE/PRSI. As I understand, you are only liable for income you bring into Ireland. So if you get paid into a BoI account, you are liable for all of that income. You haven't mentioned if you are working as a contractor or what so I'm assuming that you are getting 100% salary.
If you establish and use a local bank, you will probably find yourself liable to tax in that jurisdiction. Tax has to be paid somewhere!
Which brings up the question, what do you mean "tax free"? Does the jurisdiction simply not have an income tax, or is the company using some loophole to avoid paying it?
3. If you establish an offshore account, you will only be liable to Irish tax on the money you bring back into Ireland. However, that brings up teh question of how to use the money sitting in the offshore account. You can't just use it to fund a lifestyle in Ireland when you return (Wasn't that what Ansbacher was all about???) as you are then evading income tax.
Ideally you will want to be able to pay the income tax in some low-tax country with a taxation agreement with Ireland, so you pay the tax in the low-tax regime and then transfer the funds back to Ireland with no further liability.
Most people I know with offshore accounts are not Irish, do not have Irish ordinary residency, and are intending to go back home with their loot at the end of a given period.
I'd advise you to get professional advice ASAP.