This is a simple method to cook yu choy. It is the perfect example of the food blogging trope: "quick and easy". I literally make this a few times a week, multiple times a year, whenever I have yu choy in my fridge (which is a lot of the time).
Bring about 4 inches of water to a boil in a medium pot over high heat. Add the salt and oil.
Add the yu choy upright into the pot so the stems are submerged and the leaves are above the water. Cook for 30 seconds then push the leaves into the water. Cook for another 15 seconds then drain the water thoroughly.