Tourist Visa Enquiry-Ricardo Narvaez

I am Nicaraguan and am traveling to Vietnam through Hong Kong. I will arrive in Hong Kong on the 23rd of December and go straight to Hanoi. Then on the 31st of Decemeber i will arrive in Hong Kong and stay one day in Hong Kong and leave on the 1st of January.

I understand I have to apply for a visa in the embassy of China in Costa Rica, what documents do I need, and how much do I have to pay to apply for it. Can these documents be sent by courier?