I did the top 25 world travel destinations earlier in the week and here’s the one for Asia. Some of them, especially the ones in the top ten are the same as the world one.
1) Bali, Indonesia

2) Siem Reap, Cambodia

3) Phuket, Thailand

4) Hoi An, Vietnam

5) Kathmandu, Nepal

6) Hanoi, Vietnam

7) Koh Samui, Thailand

8) Bangkok, Thailand

9) Lombok, Indonesia

10) Tokyo, Japan
11) Goa, India

12) Chiang Mai, Thailand

13) New Delhi, India

14) Hong Hong SAR, China

15) Koh Tao, Thailand

16) Singapore, Singapore

17) Beijing, China

18) Jaipur, India

19) Agra, India

20) Kyoto, Japan

21) Ho Chi Minh City, Vietnam

22) Palawan Island, Philippines

23) Panay Islands, Philippines

24) Pokhara, Nepal

25) Seoul, South Korea

The link to full details about all the destinations is here on Trip Advisor.
The links to the photos which are not from the free WordPress photos and my personal collection are under the name of each destination. Bali, Pukhet, Kathmandu, Hanoi, Koh Samui, Lombok, Goa, Hong Kong, Koh Tao, Beijing, Ho Chi Minh City, Palawan Island, Panay Island, Seoul