Guano was harvested as a source of nitrates and was the richest commodity at the time. As usual, when work was back-breaking and soul-destroying, imigrant labour was called for.
The Chinese immigrants were mostly Hakka and Hokkien from Fukien province and other southern provinces of China. They saw a way out of poverty to the West...but into another field of poverty. Guano dust was hazardous to health, mainly respiratory. The work was incessantly hard; that and the mental stress / loneliness on those unihabited islands off the coast often led to suicides. There was no way back after you had sold your soul to the 'transporters'....er..labour agents.
The chinese labourers inisted on part payment as rice rations whilst attempting to send any money back to family in China. What intrigued the locals (Spanish speakers) was the ritual of stopping work before noon to cook the rice and then the mass lunch break. The chinese words for "cook rice" and "eat rice" (cze fan and chi fan) sounded remarkably similar to non-Chinese speakers and they invented a new 'Spanish' word for the combined ritual - 'chinfa'.
Thus, 'chinfa' has become the local Spanish word for 'Chinese Restaurant' and it is the most popular "foreign" food in the country.
As more waves of immigrants entered the country, even in the 1960s from Hong Kong, the cuisine has changed to the more refined Cantonese style, although the vestiges of the old peasant food of the Hakka still exist.
Hakka is a seemingly polite but actually derogatory term that means "Guest People". It refers to the once proud and ruling tribes of the Northern Han people, who live predominantly in the provinces of Guangdong, Jiangxi, and Fujian in China. Military defeat, famine, oppression and social stigma kept them moving in waves of migrations to nearly all of China, always guests and never 'belonging' nor owning land.
There is a saying, "If your pig is eaten or your baby stolen or sheer bad luck befalls you; look to a Hakka to blame."
Whenever there is trouble or times are hard , Hakkas are the first to be driven out. In a series of migrations, the Hakkas moved, settled in southern China, and then migrated overseas to various nations throughout the world - Taiwan, Singapore, Malaya, USA, Canada, Chile, Peru etc. Mysteriously, some are still found in northern Chinese provinces and it is not clear if those are retrograde immigrants or those who never left. The news programs in Xi'an are read in Hakka, even though it is not supposed to be a Hakka heartland.
The Hakka have had a significant influence on the course of Chinese and overseas Chinese history: in particular, they have been a source of revolutionary, political and military leaders. The sad thing is that most Hakkas will not admit to being Hakka, preferring to pretend to be whatever tribe is predominant - Cantonese, Hokkien, etc They speak the common dialect to outsiders but reserve their distinctive dialect for home use. Their food is salty, fatty and "aromatic" (which is an euphemism for smelly); but mostly cheap....er....."economical". 
Regards,
MTF (proud to be 46% hakka)
