Do you know martial arts? How to say kung fu in English? Is that so?

Do you know kung fu?

or

Do you practice kung fu?

If you use "what can you do with kung fu" incorrectly, the other person will not understand your question.

But do you know kung fu? Come and ask.

In western countries, the common concept is that "Kung Fu" stands for China traditional martial arts, and "Wushu" stands for competitive martial arts and performing martial arts. So if you are asking about competitive martial arts, you should use "martial arts" instead of "kung fu" in the sentence.