Grate the pear and onion using the large holes on a box grater, and grate the ginger using the small holes. Transfer to a medium bowl, and combine with the garlic, soy sauce, sesame oil, brown sugar and gochujang. Add the steak and toss to combine. Cover and refrigerate for at least 2 hours or overnight.
Meanwhile, make the sweet and spicy red pepper aioli. Mix together all the ingredients in a small bowl. Cover and refrigerate until you’re ready to serve.
Heat a skillet over medium-high heat with vegetable oil. Once hot, remove the steak from the marinade and place in the skillet in a single layer. Let cook for 2-3 minutes until it starts to brown and caramelize. Flip and cook for another 2-3 minutes on the other side. If needed, work in batches and add more oil.
Serve the steak over a bed of rice with kimchi, vegetables, and a generous drizzle of sweet and spicy aioli. If desired, garnish with green onion and sesame seeds.