electoralism

Wonder if he got a lot of Republican votes and that bolstered his numbers?

This has to be part of the story, at least. Bill de Blasio won 73.15% of the vote in his first election, with the Republican candidate taking 24.31%. Curtis Sliwa only won 7.1% of the vote (as of this comment, with 91% reporting), so a sizeable chunk of Cuomo's 41.6% must be Republican voters unless huge numbers of them stayed home. I assume will get some more detailed data on this in the coming days.