Prepare marinade. Combine chopped pear, soy sauce, brown sugar, garlic, ginger, sesame oil, and black pepper in a blender and puree until smooth. Pour marinade over rib eye, tossing to coat. Let sit for 20 minutes.
Meanwhile, make garlic aioli. Combine mayonnaise, garlic, and lemon juice in a medium bowl. Season with salt and pepper and let sit for 20 minutes.
Make dressing for slaw. Whisk together rice vinegar, soy sauce, olive oil, sugar, gochugaru, and sesame oil in a medium bowl. Combine green and red cabbage, scallions, mint, and jalapeno in a large bowl. Add dressing and toss to coat. Set aside.
Heat 1 tablespoon oil a large saute pan over medium-high heat. Add bulgogi and cook until browned and caramelized, about 5 minutes. Remove from heat.
Assemble sandwiches. Spread garlic aioli on the bottom sandwich buns and top with bulgogi and spicy slaw. Top with remaining bun and serve immediately.
Notes
Gochugaru is Korean chili powder and can be found in most Asian markets. You can omit it for a mild slaw.You can make the garlic aioli up to 5 days in advance.