kissing a blind mans wife

This came up before.

I don't get why it's a "riddle," as the answer seems too pedestrian/ obvious.

Lots of possibilities.

Guy who can't speak writes it, shows the writing to an intermediary, who reads it to the blind man.

Guy who can't speak traces the words on blind man's palm.

Guy who can't speak types it in braille or into one of many possible devices owned by the blind man.

Etc., etc.