This is how you do it:
First, you need to find the Tweet ID. You do this by clicking on the "time" of the tweet (such as 59m, 8h, Aug 11, etc). It will take you to a URL like:
https://twitter.com/ToddWitteles/status/653065807287742464
From there, just take the number at the end above (after /status/) and just put it in a [twitter] tag, as shown below:
[twitter]653065807287742464[/twitter]
It will look like this:
https://twitter.com/twt/status/653065807287742464
This also gives readers the ability to retweet, favorite, or follow the tweeter, right from PFA!