The iOpener is an insulated, heat-retaining bag that can be heated in a microwave and used to transfer heat to the adhesive along the edge of an iPad or similar device.
I cannot imagine why not. I wouldn't put it in the microwave WITH food it'll probably make your iOpener stink but theres no reason you couldn't reheat your pizza, then put your iOpener in the microwave, and cook ramen afterwards. No special microwave required