Allow the pork to stand at room temperature for 20 to 30 minutes before grilling. Grill over Direct Medium heat until barely pink in the center, 12 to 15 minutes, turning once. While the pork is cooking, divide the tortillas and wrap 6 each in 2 foil packages. Grill over Direct Medium heat for 2 to 4 minutes to warm them. Cut the pork crosswise into very thin slices. Serve the sliced pork wrapped in warm tortillas with the salsa.