first off, i never really liked this lock method, it looks insecure and might temp a thief to give it a try.
so here is a strategy to break it, frist let the air out of the rear tire, then take a pair of bolt cutters, cut off half the spokes from the rear wheel, typically there are 18 or 20 to cut, cut the ones closest to the lock position, this will reduce the rim tension. now cut the rim and tire with the bolt cutters. the rim is thin alu and will breek easily. the bead is a thin kevlar and will break easily. the tire and tube is rubber, easy enough. now flex the rim slightly and slip the u lock off. or make another cut and remove that part of the wheel to get the u lock off. now recieve your new bike.