In a medium bowl, mix salt and sugar in water until dissolved. Trim the tenderloins of excess fat and silver skin and submerge them in the brine; let soak for 1 1/2 hours refrigerated.
After 1 hour of brine time heat a gas grill until fully heated on high. Remove the tenderloins from the brine and pat dry; lightly pepper them.Place the pork on the hot grill grate, close the lid and grill for "7" minutes (set your timer). *The grill will not flame up because there is little to no fat on the meat. Turn the pork over, close the lid and grill for another "6" minutes. Turn the heat off on the grill and leave the pork to continue to cook for another "5" minutes with the lid closed. Insert an instant read thermometer in the middle of the thickest part of the tenderloin. It should read 145-150 degrees, if not close the lid until it does. Remove the meat from the grill and allow to rest for 5 minutes before carving, cutting across the grain into serving pieces.
.**Can be done in an iron skillet with a lid on top of the stove using the same method.