Re-stealing is a very important and vital tool especially in SNGs and late in MTTs.
As someone pointed out, DO NOT re-steal if your raise gives your opponent the correct odds
to call. Also, you must be certain that he is on a steal and not raising with a legit hand (i.e. has he been stealing often?)
A re-steal should usually come in the form of an all-in, but it is a risky play and must be done so at extreme caution.
When you are raised by a late position player and you hold a premium hand in the blinds, you should push all-in rather than call. Many times this looks like a re-steal and you will get calls.