Jose is the short, fat one and is always quick to say that he's the "bre-ains" of the two. Manuel is the skinny one and possibly, the dumber of the two. They first appeared in Two Crows From Tacos, an underrated 1956 gem by Friz Freling and perhaps one of the most controversial cartoons he ever made.
The biggest controversy over this one are the sterotypes portrayed here. Even though the stereotypes are horrific, the art, slapstick, and dialogue are what make it work. Art Davis, I believe, animated a huge bulk of this short and Virgil Ross (seemingly) animates the scene where Jose and Manuel beat up the cactus for having their "grlass-hopp-er". There's also a very unique ending to this cartoon. Instead of an iris out, we get to see a beautiful Mexican sunset as they sing their favorite song, offbeat but happily, with the immortal words, "That's all, folks!" written over the background.
The two crows reappeared in a 1959 Speedy Gonzales cartoon called Mexicali Shmoes (this time as cats), where they try to catch Speedy the same way they tried to catch their grasshopper as crows. With the same result, of course! It's probably my favorite cartoon the two crows were in. It was also nominated for the 1959 Academy Awards for Best Animated Subject and introduced Speedy's cousin, Slowpoke.