It is possible for you to get a China tourist visa in Hong Kong.
The Commissioner's Office of China's Foreign Affairs Ministry in the Hong Kong SAR provide the below service:
1. Regular service: 4 working days including submission day (e.g. Submission on Monday and collection on Thursday)

2. Express service: 3working days including submission day (e.g. Submission on Monday and collection on Wednesday

3. Rush service: 2 working day (including the submission day. e.g. If visa application is submitted on the morning of Monday, collection time is on the morning of Tuesday; If visa application is submitted on the afternoon of Monday, collection time is on the afternoon of Tuesday)