Place Asian pear, kiwi, and soy sauce in a blender; puree until smooth. Transfer puree to a large resealable plastic bag. Add beef slices; shake to coat thoroughly.
Pour beef mixture into a large bowl; add brown sugar, peeled ginger root, ginger slices, garlic, chili oil, sesame oil, honey, red pepper flakes, salt, and black pepper. Cover with plastic wrap and let marinate in the refrigerator, at least 3 hours.
Preheat an outdoor grill for high heat and cover grate with aluminum foil.
Remove beef from the bowl, discarding marinade, and cook, covered, on the preheated grill until browned, about 10 minutes. Turn beef slices and cook until second side is browned, about 5 minutes more.