First, prepare the soba noodles. Bring a big pot of water to boil. Add the noodles and cook for 5 minutes. Drain and immediately rinse the noodles under cold running water until the noodles are cool. Set the noodles aside in a colander to drain completely.
Next, prepare the sauce. Combine the perilla oil and soy sauce in a small bowl. Use chopsticks or a spoon to mix vigorously until the oil and sauce are well combined. Set aside.
Now we make the nori and sesame seed topping! Tear the sheets of nori into small pieces. Place it in a small food processor. Add the roasted white sesame seeds. And chop/blend/grind until you've have a nice powder-like mixture.
Now we plate! Divide the noodles between two bowls. Drizzle the perilla oil and soy sauce mixture on top (divide evenly between the two bowls). Use chopsticks to gently toss the noodles with the sauce until mixed.
Place 1-2 tablespoons of the nori and sesame seed topping on top of the noodles. Then top with the chopped green onions.
Mix, mix, mix, and then eat! ^_^