I doubt if many beauty salons are actually open on Sundays. I used to go to Elizabeth C Beauty Clinic tel: +353 91 566729)
but I don't think they are open on Sunday.
Probably some of the leisure centres...maybe the radisson SAS hotel might do it as they have a nice lesiure centre and pampering place there.
sounds like you backed a winner this weekend cc. Personally prefer the ardilaun hotel on taylors hill but better half prefers harbour hotel in centre of town as she can '' walk to the shops''. harbour hotel is central but no treatments unless of course you try you hand at massage yourself ! not sure about if ardilaun have spa treatments but they have a smashing leisure centre and the food is really nice. absolutely love this walk on a nice day ( dry at least) turn left outside hotel for about 3/4 mile, turn left down to salthill, turn left at that place where galway corp. threw three bags of cement on the road and called it a roundabout, walk along prom back into salthill, turn left at next big junction and back at hotel again. lovely.
Looked into the Ardilaun alright Cu, but not open on Sunday. Looking forward to the annual trip, actually staying in the Forster Court. Used to work in a restaurant in Salthill, so know the walk you're referring to pretty well.