In a small skillet over medium heat, toast the sesame seeds until browned, 3-4 minutes.
Set aside 1 tablespoon of the toasted sesame seeds in a small bowl for garnish.
Add the remaining sesame seeds to a blender and allow to cool.
Prepare the sauce
To the blender, add the vegetable oil, sesame oil, soya sauce, vinegar, mirin, ginger and 2 tablespoons water. Blend until smooth and set aside.
Cook the ramen
In a large pot, bring 2 quarts of water to a boil. Add the ramen and cook until tender. Drain the noodles in a colander, then rinse with cold water and allow to drain again.
Putting it together
Add the noodles to a large bowl. Add the chicken, half of the green onions and the sesame sauce. Toss until well coated.
Serve topped with remaining sesame seeds, green onions. Drizzle chilli oil as desired.