There IS NO 1892 NY State Census covering NY County (Manhattan) available online or ANYWHERE. The copy/original held by NY State was destroyed in the 1911 fire at the NY State Library and apparently NY County either did not keep a copy or lost its copy.
There is an 1890 census covering Manhattan and parts of the Bronx and known commonly as the "Police Census" (enumerated by the police, hence the name). Some of these books have been lost also. However, the remainder have been microfilmed. The microfilms are available at the Municipal Archives in NYC and through the LDS (and maybe other places also-I don't know). The stevemorse website has a wonderful tool for finding which book a particular address can be found in and the LDS microfilm number.