Wilma I would not call it a racial idiom, more directed at nationality. Lily will be happy I found Dutch Bargain or Wet Bargain meaning a deal made over drinks as the Dutch were known as steady drinkers.
Dutch tack I did not find but am wondering about the word tack
It could be horse tack, the tack of sailing or a metal tack or nail.

For more Dutch idiom see:
http://homepages.cwi.nl/~sjoerd/dutch.html
A Dutch Auction goes in reverse from high to lower prices till sold.

By the way, this site says Pennsylvania Dutch are really Deutsch or German.