Cut pork tenderloin into 1-inch slices and pound each slice to 3/4 inch with the flat side of a chef's knife blade.
Sprinkle the salt and pepper over both sides of the pork slices. Heat the oil in a large, heavy bottomed skillet until shimmering. Working in batches of no mare than six slices to avoid overcrowding, sear the medallions without moving them until browned on one side, about 80 seconds (the oil should sizzle but not smoke). Turn the medallions with tongs to avoid scrapping of the sear; sear until the meat is mostly opaque at the side, firm to the touch, and well browned, about 80 seconds. Transfer the pork to a plate; continue with one of the pan sauce recipes that follow using the drippings in the pan as the base for the sauce.