Wash the bean sprouts 2-3 times in cold water and remove the bad bean heads and discard broken sprouts keeping only long nice sprouts.
Put the bean sprouts in a large saucepan with water and salt; cover the top. Cook for 10 minutes in medium heat then turn the heat off. Let it sit for 3 minutes (Do not open). Leave about 3 table spoons the liquid pouring out the rest.
Season with spring onions, garlic, chilli powder, sesame seeds, sesame oil and black pepper. Mix with your hands very gently or a lot of bean sprout heads will fall off.
Place seasoned the bean sprout mixture on a plate and discard the heads.