Combine pear, garlic, soy sauce, chilli flakes, ginger, sugar, and sesame oil in a large resealable plastic bag or medium bowl. Using a sharp knife, slice meat into very thin strips.* Add to marinade, seal bag, and squish everything around until the meat is coated. Let sit at room temperature 30 minutes, or chill up to 8 hours.

Heat 1 tbsp vegetable oil in a large skillet over medium-high until oil is shimmering. Remove half of meat from marinade, letting excess drip back into bag; season lightly with salt and cook in a single layer without moving until lightly browned, about 1 minute. Toss meat and continue to cook, tossing occasionally, until cooked through and crisp at edges, about 3 minutes. Transfer to a plate. Repeat with remaining 1 tbsp vegetable oil, remaining meat, and more salt.

*For this basic bulgogi recipe, cutting the meat into very thin strips allows it to absorb the hot-sweet-salty marinade in minutes, not hours.