Mexcian Cheese Selections for Quesidillas?
perhaps it was oaxacan cheese, which is similar to mozzarella - it is white and melts very easily. It has a pretty mild flavor as well.
Although, there is a chance you had queso asadero... it's also pretty mild and a good melting cheese.
If I were making a quesadilla, I'd go with oaxacan cheese inside for its good melting/stringy quality, then sprinkle some queso anejo shavings on top (sort of like a parmesan/romano, sort of texture). That would give it some more flavor. Then again, there are countless options aside from just the cheese, but that is another discussion...
You have a couple of cheese options for classic melty quesadillas. My favorite is Chihuahua cheese, a mild melting cheese apparently introduced to Northern Mexico by Mennonite missionaries (globalization isn't anything new!). You can find similar melting cheese sold as Queso Quesadilla. I also enjoy that.
As for the other postings: Queso blanco/ añejo/ boricua/ ranchero are solid, non-melting cheeses. (Boricua is Puerto Rican, for that matter.) These are more common cheeses in Mexico and are often eaten crumbled. They have a consistency like farmer cheese, feta, or any other crumbly white cheese.
Enjoy your quesadillas!