Combine Marinade & Sauce ingredients in medium bowl. Reserve 3/4 cup for basting sauce. Place beef steaks and remaining marinade in food-safe plastic bag; turn steaks to coat. Close bag securely and marinate in refrigerator 15 minutes to 2 hours.
Meanwhile, prepare basting sauce. Pour reserved 3/4 cup marinade into small saucepan; bring to a boil. Reduce heat; cook 15 to 20 minutes or until reduced by half and slightly thickened, stirring occasionally. Set aside.
Cook quinoa in broth in medium saucepan according to package directions. Stir in spinach, pomegranate seeds and walnuts. Keep warm.
Remove steaks from marinade; discard marinade. Place steaks on grid over medium, ash-covered coals. Grill, covered, 7 to 10 minutes (over medium heat on preheated gas grill, times remain the same) for medium rare (145 degrees F) to medium (160 degrees F) doneness, turning occasionally and basting with sauce.
Carve steaks into slices; season with salt, as desired. Place quinoa on serving platter; top with cheese. Arrange beef around quinoa. Garnish with pomegranate seeds, if desired.