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 in a large pot with water and salt; cover the top. Cook for 10 minutes in medium heat and turn the heat off. Let it sit for 3 minutes (Do not open!). Leave about 3 table spoons the liquid and pour out the rest.
Season with chopped green onions, crushed garlic, Korean red pepper 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 in a plate and discard the heads.