My paternal grandfather is the oldest person I know anything about who had the name. He was born in Rosiska (the obituaries disagree about whether that is in Czechoslovakia or Ukraine). He passed away before I was born so this is about the extent of my knowledge about him that's relevant to genealogy.
It seems that most immigrants romanized it as "Sczmoniak", but my grandfather did it as "Shimoniak" instead.
An ancestry DNA test leaves open the possibility that it may be Jewish.