yeah i got the recipe out of the How to Grill Cookbook I bought with the grill.
The recipe called for cheese, cilantro, scallions, red plum tomatos, and jalapenos.
We left out the cilantro and substituted yellow onion for the scallions. I had to add some meat so we grilled some thin chicken breasts with a little baja chipotle lime marinade and then sprinkled with some cayenne pepper and black pepper... sliced 'em into strips and added them into the quesadillas before grilling them.
I would recommend using a large wide spatula (like for fish or something)because I nearly dumped all of the stuffing into the grill when trying to flip them!
Of course you can add in whatever you want! be sure to turn the grill down to LOW before placing the quesadillas on it!
Also be sure you butter outside of tortillas really good... And I would even oil the grates with spray pam (watch the flames!) or with a basting brush and some oil. I grilled em about 2 minutes per side.