You can find Duritos at almost any supermarket. As for freshmade, they are sold mostly by street vendors. I'm not sure what the street vendor situation is in Pasadena, but in the IE, you can try the Van Buren Drive In Swapmeet in Riverside.
128 N 5th St, Montebello, CA 90640
I googled duritos and look what popped up:
Here's an image:
So that's what they're called... I typically see street vendors peddling these from carts, particularly near schools around the time the kids let out.