Police on Wednesday arrested Gerber Cruz, 32, in the slashing incident on Jerusalem Avenue in Uniondale.
Detectives said that Cruz, of 299 Jackson Ave., "intentionally slashed" a man, 31, using "a large razor or knife blade" and cut him from his right ear to his mouth.
The man was treated for his injuries at a hospital and released, police said in a news release.
Police did not provide a reason or motive in the slashing incident.
Cruz also was charged with criminal possession of a weapon and was ordered held on $500 cash bail at his arraignment Thursday in First District Court in Hempstead, a spokesman for the district attorney's office said.