Do Chinese (PRC) universities offer CS/CSE Masters programs taught in English?
If yes, do these programs require mandatory HSK scores to enroll?
If you just search for the universities, you will see that each of them has specific guidelines regarding your proficiency in Chinese.
For Tsinghua university, here is what I find : http://www.tsinghua.edu.cn/publish/then/5975/index.html , but I can't find anything about HSK requirements. My guess is that if the courses are taught in English, you are more likely to be asked to provided your TOEFL scores instead.
Now you might want to look at other universities, you should get all the information you need on their websites.
So, yes, Chinese universites do have CS Masters programs in English, and it appears that they don't required HSK (but you should contact the International Office of each university to be sure of that).