Their best bet might be a work visa. But you can only apply for that if you already have an employer in the States that wants to hire you. They could come into the US on a tourist visa and seek employment, and start the application process once they find something for sure. There are certain countries from which you can visit the States for 90 days without a visa, but I do not believe that applies for Peru or China. I'm not a 100% sure, so check. You cannot change your status if you're in the country with a tourist visa, though.
You can take a look at
www.bcis.gov for more information on immigration. I migrated into the States last year, but I don't feel that I can give you valid information as my situation was quite different.
However I will give you one piece of advice... They should look into every action with great detail before doing anything. Should they end up going with a temporary visa, they should make sure they do not extend their stay beyond the validity of the visa. The immigration services take their rules extremely seriously, nowadays more than ever. Furthermore, always tell the truth, regardless of what it is and whether you want to or not. Not volunteering crucial information = lying, as well.