Clean and cut the squid and shrimp into appropriate sizes.
Slice the onion, green onion, and garlic.
Heat cooking oil in a pan, then stir-fry the garlic and green onion to bring out the aroma.
Add the squid and shrimp to the pan and stir-fry over high heat.
Add the onion and stir-fry together.
Season with soy sauce, sugar, and pepper.
Continue to stir-fry until all ingredients are cooked, then drizzle with sesame oil.
Serve on a plate to finish.