Put 2 chicken breasts in a pot. Pour-in enough water to cover the chicken breasts. Bring pot up to a boil. Once boiling, reduce the heat to a medium-low. Let chicken breasts gently simmer for 15 minutes.
Slice onion into very thin slices. (The thinner the better!) Then place the onion slices in a bowl of cold water. Soak in the water for 15 minutes to reduce the sharp flavor.
Cut stem off the oyster mushrooms. Use your hands and break each piece off each other. Then rinse under cold water. Bring a small pot of water up to boil. Season the water with few shakes of salt. Then boil the mushrooms for 15 seconds. Drain the mushrooms and cool-down under cold water. Then use your hands and squeeze the water out of the blanched mushrooms. Set aside.
Finely dice the spring onion stalk.
After 15 minutes, take out the chicken breast pieces and shred with two forks. Note: If you see pink, place back in boiling water for 5 more minutes.
Take out a large mixing bowl. Add-in the shredded chicken, oyster mushrooms and thinly sliced onions. Then add-in all of the listed ingredients under 'Seasoning Sauce'. Give a thorough mix.
Serve with a bowl of hot rice. Bon Appetit!