This is a list with special shops and markets in Dublin where you would get special stuff.
Food Shops[]
Fresh
Supervalu
see also Asian Shops, Indian Shops, Eastern European Shops, Health Shops
List of Shops at Yelp.ie. But it's messy to find anything particularly there and it's not known if the shops have what you look for.
Food Markets[]
Moore Street Market, Food Coop
Lists of markets at VisitDublin and at Yelp.ie.