Looks like I'm the first person to post here. Good luck Woof Advisor!
In the meantime, I will suggest some great dog friendly walks around south County Dublin/Wicklow border.
Shankill - end of Quinn's Road just outside the village - park and walk along a country lane which opens out onto both beach and endless fields. There are signs in the field as you enter about keeping your dog in a lead however this seems to be mostly ignored and generally dogs are very well behaved and nobody seems to mind. As long as you scoop the poop you should be fine.
Ticknock Woods - great for the fitter dog owner - it's uphill to the top! However there are routes around the side of Ticknock which are great fun for dogs. Can be very muddy under paw in the winter time.
Killiney Hill Park - probably the most dog-friendly place in Dublin. There's also a great cafe which has a place to hitch up the dog lead and there are dog bowls. Seats outside too if you don't want to leave your canine companion.
Rathmichael Wood - off Ferndale Road in Rathmichael - nice shortish loop with great views and forest trails. Above Rathmichael Wood, off Puck's Castle Lane, is the Lead Mine which offers lots of woodland tracks and trails.
These are just a few to get started - I will add more another time.