Hi. Unfortunately, as to date, there is no driving test center in Shiga. The nearest driving license center is in Kyoto with the address shown below:
Kyoto License Center
647 Furukawa-cho Hazuka-shi Fushimi-ku
Tel: 075 631 5181
You may also inquire beforehand via call if they cater to Vietnamese driving lessons since most driving lessons in Japan are held in straight Japanese/English only.