Yes! You can fill them, and skip frying them and freeze them on parchment paper, and then transfer to a container with a lid and keep them for up to three months. To reheat, you can microwave them for one to two minutes, fry in the pan, or in a toaster (with the open side facing upwards). Personally, if possible, I prefer to freeze the filling, and then later defrost and add to the tortillas to get the crispiest quesadillas possible.