2 bunches beets (3 to 4 pounds with greens), greens removed, chopped, washed, and drained with some water clinging (about 9 cups greens) 2 pork tenderloins, (12 ounces each), trimmed of excess fat Coarse salt and ground pepper 4 tablespoons olive oil 2 teaspoons Dijon mustard 2 teaspoons plus 1 tablespoon red-wine vinegar 2 garlic cloves, smashed 2 tablespoons toasted pine nuts