In a small saucepan whisk the sauce ingredients. Bring the sauce to a simmer over medium heat and simmer gently for about 5 minutes, whisking occasionally. Set aside to cool at room temperature.
In a small bowl mix the rub ingredients.
Lightly coat all sides of the tenderloins with the oil and season evenly with the rub, pressing the spices into the meat. Allow the tenderloins to stand at room temperature for 15 to 30 minutes before grilling.
Prepare the grill for direct cooking over medium heat (350° to 450°F).
Grill the tenderloins over direct medium heat, with the lid closed, until the outsides are evenly seared and the internal temperature reaches 150°F, 15 to 20 minutes, turning about every 5 minutes. Remove from the grill and wrap with aluminum foil. Let rest for about 15 minutes or until cool enough to comfortably handle.
Cut the tenderloins crosswise into quarters. Pull the warm meat apart with your fingers or use two forks to shred the meat. In a large bowl moisten the pork with as much of the sauce as you like. Serve on a bed of soft polenta, if desired.