You need provide the following documents to Chinese embassy or consulate in UAE for Chinese tourist visa application:
1. Original passport with blank visa pages and validity of more than 6 months;

2. UAE resident visa valid for more than 6 months. (Excluding non-GCC applicants);

3. Application Form which must be completed neatly and signed by the applicant;

4. One passport photo (and the photos of the applicant's accompanying persons included in his/her passport if they plan to travel with the applicant.);

5. Copies of the data pages of the applicant's passport and UAE resident visa.

6. A No-objection letter from the applicant's company stating his or her position ,monthly or yearly salary;

Your friend who holds a tourist visa to Dubai can't apply for Chinese visa in UAE.