"Can you believe @CNN is 'milking' it for almost 3 hours? Too long, too many people on stage!"
The two GOP presidential rivals sparred in the first GOP presidential debate last month.
"This is a splendid opportunity for the global jihadists," the presidential candidate said.
Jeb Bush's poll numbers have diminished in recent weeks.
“We need people with an aggressive tone, and we need people with tremendous energy."
Several of his GOP presidential rivals would support a shutdown over the issue.
Once the Iowa front-runner, Walker got just 3 percent in the state in a recent poll.
Paul said he was the only candidate who believes "in your right to be left alone."
Fiorina addressed Trump's recent remarks about the presidential candidate's face on Friday.
The event's venue has a capacity of about 20,000.