Blanched Choy Sum with Sizzling Oil

Name: Blanched Choy Sum with Sizzling Oil (You Lin Cai Xin 油林菜心)
Cuisine: Chinese
Ingredients: A small strip of red chilli or red pepper for colour (optional); 4 tbsp cooking oil; 2 spring onions; 1 tsp salt; 2 tbsp light soy sauce diluted with 2 tbsp hot water from the kettle; 300 g choy sum; 10 g piece of ginger