For aïoli, combine all ingredients in small bowl; mix well. Chill at least 1/2 hour. Heat grill or broiler. For burgers, combine turkey, oats, garlic, Worcestershire sauce, oregano, salt and pepper in large bowl; mix lightly but thoroughly. Shape into 6 large patties, about 1/4-inch thick. Place one mozzarella ball in center of each patty; shape burger mixture around cheese so it is completely hidden; reshape into patty. Grill or broil 4 inches from heat 5 minutes on each side or until centers are no longer pink (170°F). Arrange burgers on bottom halves of buns; top with aïoli, roasted pepper pieces, watercress and bun tops.