There is nothing that says "Irish" more than seafood. Steamed mussels are not only delicious, they are easy to prepare.
Rinse off your mussels first in cold water. Discard any that are open. Melt a half stick of butter in a saucepan over medium heat and saute a clove of minced garlic in it. Add a cup or so of dry white wine and some chopped scallions. Pour in your mussels and steam until open.
Serve immediately with some lighter Irish beer, like Harp and sliced sourdough bread with a hunk of good Irish white cheddar. For extra color and freshness, serve the mussels on a bed of watercress leaves.