Place pork vertically on a cutting board (with cut side facing you) and open it into a rectangle. To do this, cut along the entire length of the pork, 1/2 inch from the edge of the meat with your knife at a 90-degree angle to the cutting board. Do not cut all the way through, stopping about 1/2 inch from the board. Starting at the base of the cut, change the angle of the knife so that it is parallel to the cutting board (flat). Cut inwards along the entire length of meat, making slow, shallow cuts and keeping your knife 1/2 inch above the cutting board. With your other hand, gently pull the meat away from your knife as you “unroll” it.