The skinny
I think I have heard both.. "to have the skinny on," and "to get the skinny on" something.. skinny meaning "knowledge" are both these uses correct?
Yes those uses are correct. It means news, information, gossip. This use of the word is said to have originated in the armed forces in the 1940s and might be jocularly based on 'the naked truth' as in "getting down to the skin" of a story, beneath the flourishes and frippery.