I put out a call on twitter for Kid/YA books featuring multicultural protagonists, and below are the responses. Feel free to add more suggestions of funny books in the comments and I'll update the list.
Younger Readers
NERDS by Michael Buckley
THE WATSONS GO TO BIRMINGHAM by Christopher Paul Curtis
BINDI BABES by Narinder Dhami
OPERATION REDWOOD by S. Terrell French
KIMCHI AND CALAMARI by Rose Kent
YEAR OF THE DOG by Grace Lin
ALVIN HO by Lenore Look
RUBY LU by Lenore Look
LUV YA BUNCHES by Lauren Myracle
8TH GRADE SUPERZERO by Olugbemisola Rhuday-Perkovich
THE TRUE MEANING OF SMEKDAY by Adam Rex
DAVID MORTIMORE BAXTER series by Karen Tayleur
ONE CRAZY SUMMER by Rita Williams-Garcia
BOBBY VS. GIRLS (ACCIDENTALLY) by Lisa Yee
MILLICENT MIN, GIRL GENIUS by Lisa Yee
STANFORD WONG FLUNKS BIG TIME by Lisa Yee
Young Adult
DOES MY HEAD LOOK BIG IN THIS? by Randa Abdel-Fattah
TEN THINGS I HATE ABOUT ME by Randa Abdel-Fattah
THE ABSOLUTELY TRUE DIARY OF A PART-TIME INDIAN by Sherman Alexie
FREAK MAGNET by Andrew Auseon
THE MAKING OF DR. TRUELOVE by Derrick Barnes
SHE'S SO MONEY by Cherry Cheva
WHALE TALK by Chris Crutcher
WE WERE HERE by Matt De La Peña
SOPHOMORE UNDERCOVER by Ben Esch
SOUL ENCHILADA by David Macinnis Gill
BORN CONFUSED by Tanuja Desai Hidier
MUCHACHO by Louanne Johnson
SKUNK GIRL by Sheba Karim
MY MOST EXCELLENT YEAR by Steve Klugman
PERFECT SHOT by Debbie Rigaud
THE KAYLA CHRONICLES by Sherri Winston
AMERICAN BORN CHINESE by Gene Yuen Yang
STOP ME IF YOU'VE HEARD THIS ONE BEFORE by David Yoo
GOOD ENOUGH by Paula Yoo