Press the tofu slices gently between paper towels to squeeze out the excess moisture. Season both sides with salt and pepper. Heat the vegetable oil in a large nonstick skillet over medium-high heat. Add the tofu in a single layer and cook until well browned, 5 to 6 minutes per side. Let cool, then cut into bite-size pieces.
Meanwhile, bring a large pot of water to a boil. Whisk the kimchi brine, sesame oil, soy sauce, sugar and vinegar in a large bowl; set aside. Add the noodles to the boiling water and cook as the label directs. Drain and rinse under cold water until very cold. Shake off as much water as possible.
Transfer the noodles to the bowl with the sauce mixture; add the tofu, sliced kimchi, mesclun greens, pear and 2 teaspoons toasted sesame seeds. Toss to combine; season with salt and pepper. Divide the noodle mixture among bowls. Sprinkle with the remaining 2 teaspoons sesame seeds.