The website Canon Law Made Easy provides some interesting thoughts on the the teachings of the Church with regards to tithing.
The site does not allow copying and pasting, so you will have to go there to read the whole thing but the short answer is NO. Tithing is not required. Here's the Canon Law:
The Christian faithful are obliged to assist with the needs of the Church so that the Church has what is necessary for divine worship, for the works of apostolate and of charity, and for the decent support of ministers.
Says the site:
But note that Can. 222 says absolutely nothing about tithing, much less does it attach the penalty of excommunication to anyone who does not tithe. In fact, the current law provides no numerical figures or calculations at all. For that matter, a close look at the Latin wording will show that it doesn't actually require the faithful to give money! The terminology indicates that Catholics are to assist the Church, to come to its help as needed - and there are many different, genuine ways to do this that don't involve one's wallet.
I was wondering about this after having read the first reading form the Genesis last Sunday:
In those days, Melchizedek, king of Salem, brought out bread and wine,
and being a priest of God Most High,
he blessed Abram with these words:
"Blessed be Abram by God Most High,
the creator of heaven and earth;
and blessed be God Most High,
who delivered your foes into your hand."
Then Abram gave him a tenth of everything.