Mona in the Promise Land

To begin with, I guess I didn't quite expect the extensive amount of sarcasm that opened the novel.  In fact, it almost became irritating trying to read and messed up my reading flow.  I'm wondering if this happened with anyone else and what effect the extensive sarcasm has?  What do you think was Jen's intention by using this technique.
Also, I was very intrigued by the juxtaposition of Mona and Sherman.  Mona is deemed a Chinese-American and inspires interest in her peers due to her supposed 'foreignness'.  However, in fact, Mona is far removed from her heritage as is most of her family.  Even her mother admits to being unable to remember how to write Chinese characters.  On the other hand, Sherman is himself the immigrant.  He is from Japan and has ventured to the United States.  At first, Mona hesitates to accept Sherman.  But, Sherman mother chose his class based on the fact that there was another Asian, Mona.  Therefore, Sherman's mother actually echoes the sentiment of her peers.  Solely the fact that she is Chinese consoles her.  However, Sherman's presence highlights Mona's distance from her homeland and culture.  Just before Sherman leaves, Mona asks him to switch to American because the way he does things is weird.  How does this juxtaposition enhance or detract from our impressions of Mona and Sherman?  Would we feel the same way about each of the characters if it weren't for the presence of the other?  What do these characters say about the process of Americanization?