1) The ONLY song I found titled Cinco de Mayo was by Liz Phair....talks about breaking up, and a bullet. Don't think that is it.
2) Lyrics for El Rey David:
(No tune found yet)



Estas son las mañanitas
EH-stahs sohn lahs mahn-yah-NEE-tahs
these are the early little mornings


que cantaba el rey David
kay kahn-TAH-bah ehl ray dah-VEED
that King David sang about


y a las muchachas bonitas
ee ah lahs moo-CHAH-chahs boh-NEE-tahs
and to the pretty girls


se las cantaba así
say lahs kahn-TAH-bah ah-SEE
he sang them (to them)like this


despierta chica despierta
deh-SPYAIR-tah CHEE-kah deh-SPYAIR-tah
wake up,girl wake up


mira que ya amaneció
MEE-rah kay yah ah-mah-neh-SYOH
look,it is already dawn


ya los pájaritos cantan
yah lohs PAH-hah-ree-tohs KAHN-tahn
the birds are already singing


ya la luna se escondió
yah lah LOO-nah say eh-skohn-DYOH
the moon has already hidden itself


qué bonitas mañanitas
kay boh-NEE-tahs mahn-yah-NEE-tahs
what pretty early mornings


parece que va a llover
pah-REH-say kay vah ah yoh-VAIR
it looks like it is going to rain


así estaba la mañana
ah-SEE eh-STAH-bah lah mahn-YAH-nah
the morning was like this


cuando yo te fui a ver
KWAHN-doh yo tay fwee ah vehr
when I went to see you


pregunté al de la esquina
preh-goon-TAY ahl day lah eh-SKEE-nah
I asked the man on the corner


si me podría hacer un favor
see may poh-DREE-ah ah-SAYR oon fah-VOHR
if he could do me a favor


de apagar su lucesita
day ah-pah-GAHR soo loo-say-SEE-tah
of turning off his little light


cuando ha pasado mi amor
KWAHN-doh ah pah-SAH-doh mee ah-MOHR
when my love has gone by


y luego yo le digo
ee LWEH-goh yo lay DEE-goh
and then I tell him


le agradezco el favor
lay ah-grah-DEH-skoh ehl fah-VOHR
I thank you for the favor


le agradezco la ayuda
lay ah-grah-DEH-skoh lah ah-YOO-dah
I thank you for the help


ahora me siento mejor
ah-OH-rah may SYEHN-toh meh-HOHR
now I feel better

Found here:http://www.songsforteaching.com/LasMananitas.html