I got this recipe out of a magazine, and modified it a little bit. It's light, quick, and easy. (Tastes good, too.)
1 10 oz. package frozen corn kernels (you can barbecue 4 ears of corn first, and then cut the kernels off, but that's too much work for me)
1 avocado, cut into little chunks
1 cup cherry or grape tomatos, cut in half
1/4 cup chopped cilantro
1 bunch green onions, half of them thinly sliced, half cut into 2 inch lengths
1 Tb lime juice
coarse salt and ground black pepper
1 1/2 cups shredded Monterey Jack cheese (6 oz.)
1 yellow squash, halved crosswise and thinly sliced lengthwise
1 orange bell pepper, ribs and seeds removed, thinly sliced
For corn relish, mix corn, thinly sliced onions, cilantro, avocado, and tomato. Season with salt and pepper, add lime juice and toss to combine.
For each quesadilla, sprinkle a little cheese on the bottom half of a tortilla. Top with squash, bell pepper, onion, and a little more cheese. Season with salt and pepper and fold top half of tortilla over the filling to close. Grill on lightly oiled barbecue grates, turning once, until browned in spots and cheese has melted. (the recipe says 6-8 minutes, but mine seemed to go much faster)
Cut into wedges and serve with corn relish.
Note: the receipe said this made 4 quesadillas, but I had enough veggie filling for at least 6.