I feel rather unqualified to answer this, but "sláinte" still sounds like a toast. I don't recall it being used for anything else while I was in Ireland. Some languages do share the same word for toasts and sneezes, but it seems Gaeilge isn't one of them. Apparently it's "Dia Linn" (God be with us), based on a bit of web research. I found an interesting discussion here (and learnt a few things as well!): http://www.irishgaelictranslator.com/translation/topic101946.html

Tá slaghdán ort, a ghadaí = You've a cold, you thief! A fun saying used! Dia linn is Muire would be more common in some dialects, chosen over simply Dia linn.

As well as "Dia linn", another option is "deiseal", which means "clockwise, sunwise" ("rightwards"). This stems from the ancient belief that clockwise movement brought good fortune and anticlockwise movement brought misfortune.

It's "Dia linn".