Employer RSU's / CGT

USD dollar exchange rate on vesting date is irrelevant for CGT. Use the sale date. Deduct any money exchange expenses from the Capital Gains.
 
I found this online, but I was thinking that would only apply if I had used to euros to acquire the US dollar share, whereas I've been given them in Dollars.

Foreign exchange – the basic rule here is that CGT is calculated using euro (equivalent) values at the time of acquisition & disposal. This means that if there is a fx movement, then it will be included in the Irish tax computation.