You can download the beta version and learn Tableau by your own and also this forum is a very good place to learn by yourself. and if you have any question, you can come to the forum, lots of people here will help you
These forums are for trouble-shooting and help with Tableau products. Visa sponsorship varies by location and is not in the realm of this Tableau forum. You can try asking in the Job Listings but i doubt it will be of much help.
As Zhouyi Zhang said, sponsorship is not necessary to learn software. Actually using it is what is needed to be done. For practice you can participate in #MakeoverMonday - Twitter Search on Twitter as a lot of experts started off and honed their skills with this.