Wrap steak in plastic wrap, and place in the freezer for 30 minutes. Unwrap and slice across the grain into 1/4-inch thick slices.
In a medium bowl, combine pear, soy sauce, brown sugar, sesame oil, garlic, ginger and gochujang. In a gallon size Ziploc bag, combine soy sauce mixture and steak; marinate for at least 2 hours to overnight, turning the bag occasionally. Drain the steak from the marinade.
Thread 2-3 slices steak onto skewers. Brush with vegetable oil; season with salt and pepper, to taste.
Preheat grill to medium heat.
Add skewers to grill, and cook, turning occasionally, until charred and cooked through, about 4-5 minutes.
Serve immediately, garnished with green onions and sesame seeds, if desired.