Here's some info re. license conversion:

Foreign Pilot Certification - AOPA

141 or 61 is really your choice. I would default to 61, unless you have a good reason to do 141. In your case, you might find that a 141 school is more familiar with foreign student requirements and visas.

You cannot use a tourist visa for flight training (that's what the 9/11 hijackers did). You'll need an M-1 or F-1 visa; all large schools and some smaller ones can help you with that. Be aware that you will also get a security screening before you can start training (9/11 again).