The ex-Universidad striker, who spent the 2013-14 season with Real Zaragoza, failed to make a first team appearance at Old Trafford and could make his move to Croatia permanent.
The Chilean, who has three caps for his country, signed for United from Universidad in his homeland two years ago. He failed to make an impact at Old Trafford, however, and is yet to make an appearance for the first team.
After a brief loan spell at Wigan Athletic during the 2012-13 season, the 20-year-old spent last term in Spain with Segunda Division outfit Real Zaragoza, scoring six times in 25 appearances, and has now joined the Zagreb club for a season.
Currently leading the Croatian top flight with a perfect record after four matches, Zagreb faces Petrolul Ploiesti in the first leg of a Europa League playoff clash on August 20, and Henriquez is thrilled at the prospect of helping his new side reach the first round of the competition.
"I'm happy with my arrival at Dinamo and I want to do good things," he told the club's official website. "I have a lot of motivation and I want to prove myself, I believe that Dinamo is a great club for it.
"I want to help the club enter the group stages of the Europa League."