Savory-sweet meets Korean barbecue! Marinated flank steak, crisp vegetables and a Gochujang mayonnaise on toasted hoagie rolls.
Combine apple juice, vinegar, onion, lime juice, chili sauce, brown sugar, garlic, ginger, miso paste and soy sauce in small bowl. Reserve and refrigerate 1/4 cup marinade. Place flank steak and remaining marinade in food-safe plastic bag; turn to coat. Close bag securely and marinate in refrigerator 6 hours or as long as overnight.
Remove steak from marinade; discard marinade. Place steak on grid over medium, ash covered coals. Grill, 8 to 10 minutes (over medium heat on a preheated gas grill, 9 to 11 minutes), for medium rare (145°F) to medium (160°F) doneness, turning once. Rest steak 5 to 10 minutes before slicing.
Meanwhile, to prepare Gochujang mayonnaise combine mayonnaise and red chili sauce in small mixing bowl; set aside. In second mixing bowl, combine kimchi, cucumbers, carrots, radishes and apple. Stir in reserved marinade until combined.
Spread Gochujang mayonnaise onto bottom halves of rolls. Top evenly with sliced beef, kimchi salad mixture and top halves of rolls. Cut in half to serve.