Heat a large wok or non-stick skillet over a heat heat. Add 1 tablespoon sesame oil. Swirl to coat the pan. Add ground beef. Sprinkle with 1/2 teaspoon salt. Working quickly, use a wooden spoon to break up the beef into small pieces. Continue to brown the beef until it starts to turn very crispy on the outside. This should take about 6-8 minutes. Be sure to keep breaking up the beef with the wooden spooon.
While the beef cooks, slice the veggies if you haven't already. Add the soy sauce, brown sugar, mirin, remaining sesame oil, black pepper, and sambal oelek to a jar with a lid. (You can also use a small bowl and whisk, just make sure to whisk until all the brown sugar has dissolved.) Shake the jar until the brown sugar has dissolved and all ingedients are combined.
Once the beef is cooked through, and most of it is crispy, add the onion and pear. Cook for another 4-5 minutes until onion has completely softened. Add garlic. Cook for 1-2 minutes until softened.
Sprinkle the beef with sauce and sprinkle with green onion. Continue to cook, stirring frequently until the beef is coated and the sauce has thickened, another 3-4 minutes.
Spoon into lettuce. Top with peppers and carrots. Sprinkle with sesame seeds.