For Seasonings:
Cut open the heads and remove the intestines and beaks.
Put in a large bowl. Add flour and scrub vigorously for about 2 minutes until it foams. Rinse in cold running water until not slippery anymore. Drain.
Boil a large pot of water. Blanch the octopus for 10 to 12 seconds, drain, and then cut the heads and arms into bite-size pieces.
Make seasoning sauce by combining all the seasoning ingredients in a small bowl. Mix well.
Stir-fry garlic, ginger, green chili pepper, onion, and green onion in a pan over high heat for about 3 minutes.
Add nakji and seasoning sauce. Stir for 2 to 3 minutes.
Remove from heat, stir in sesame oil, and serve right away with rice.
