Oh, to make a long story short.
If there is no Zen, there is no Kung Fu.
If there is no Kung Fu, there is no Zen in Kung Fu.
What is your Zen?
What is your Kung Fu?
Zen is (in) Kung Fu. Kung Fu is Zen.
Single pointed mind.
Ultimately, no mind or still mind.
That is where everything starts and ends.
Yes, your mind. The body and the movements are reflections of your mind.
And yes, there is Qi to link the 2.
The beginning of understanding does not come with koans.
It becomes with foundational and tangible knowledge and with time and further understanding moves away from from hard textual information and postulation.
In Kungfu, you begin by mimicing what you are shown.
You internalize what you have been taught by doing.
Then you become it and it becomes you.
You cannot have a result without a beginning.
When you see the snow blocking your way to the road, you have to do the work of clearing it before you can get on the path.
I’ve been taking kungfu about a year at a very traditional, authentic school (I won’t mention the style) but it is my zen. I’ve just got an empty bookshelf in the house and wanted to fill it with something 
Greetings..
Chronicles of Tao; Scholar Warrior; 365 Tao.. all by Deng Ming Dao
Tao, A watercourse Way.. by Alan Watts and most other Watts books..
Yang Jwing Ming’s books are redundant but full of good stuff..
Tao Te Ching.. Jane English version and Red Pine version..
Conversations With God.. Neale Donald Walsh.. forget the religious baggage, these books are as Taoist as you can get..
Don’t forget to practice what you read..
Be well..
There are many good books but mostly in Chinese.
I would have post something deeper if it is in Chinese forum.
However, since this is English forum.
I feel limited in posting all the time.
But words do not need to be deeper.
The meaning is transparent. That is most important.
Sun Tzu 13 chapters include tactics and strategy.
De Dao Jing is about how to lead people or an Army; even run a company, nation etc.
Book of Change or Zhou Yi is to understand the rules of change.
The expanded Chinese chess gameboard has 18 line X18 line= 324 possibilities.
These are required read for me when I was growing up.
Most of the Chan or Zen books in Chinese are very deep.
Or take a while to digest.
There is no fast read.
KL linked to some good info sites.
Interpretations of Chan books usually require some knowledge of Chinese 5000 years of history and literature.
The De Dao Jing and Zhou Yi are required studies for Chan Buddhist monks.
Xi Lai Buddhist University or any other major Buddhist colleges require these courses as well.