Cheech Marin refers to Antonio Banderas as "the biggest Mexican ever seen." Antonio Banderas is 5'9", which is still taller than the average Mexican male of 5'7". But the director Robert Rodriguez, who is 6'2" really is "the biggest Mexican."
The ringtone for the cellphone that Sands gave to El Mariachi is "Canción Del Mariachi", the theme song of Desperado (1995). You can hear it for a very short time before El Mariachi answers the phone.
According to writer/director Robert Rodriguez, the idea to do a third movie in his El mariachi (1992) series came from his friend Quentin Tarantino who, knowing Rodriguez to be a fan of Sergio Leone, also suggested the title. Tarantino is given special thanks in the closing credits. - Actually Robert Rodriguez intended on making a trilogy from the get go. You can read that for fact in his book "Rebel Without A Crew".
The chain tying El and Carolina together is removed with an electric wire feed welder (used for welding) and not a blowtorch (used for cutting), removing the links closest to the cuffs. When it falls to the ground, it is whole again.
When Lorenzo is practicing shooting, he takes his brother's bottle of alcohol and places it on the wall to shoot. The drunk picks the bottle up, and while he holds it, Lorenzo shoots it. They cut away to show Lorenzo, and when they cut back to the brother holding the bottle, the bottle has broken differently, and had a label.
Sands: My name is Sheldon Jeffery Sands. I work for the Central Intelligence Agency. I throw shapes. I throw shapes, I set them up, I watch them fall. I'm living la vida loca.