Clean the squid by removing the transparent plastic-like backbone inside the squid. Remove the innards but retain the ink sac. Remove the also the beak in the middle of the tentacles by squeezing the head. Wash in running water and drain.
Just be careful not the press the eyes of the squid or it will burst. If the squid are large or just prefer to slice it, you can also slice the squid into rings.
Heat oil in the pan and saute garlic and onion until fragrant. Then add the ginger and green chili peppers and saute for a minute.
Immediately add the fresh squid, soy sauce and vinegar. Do not stir. Bring to a boil then cook the squid for about 3 minutes without covering the pan.
Remove the squid from the liquid and set aside. Continue to boil the liquid in the pan and add sugar. Let it boil until the liquid evaporates and slightly thick in consistency.
Then put back the squid and stir. Let it cook for a minute more while stirring then turn off heat. Serve hot and garnish with chopped spring onions.