While traveling SE Asia I didn't see that very often.
Besides in some rural areas (and even there), dogs turned into pets as in western "civilization" and their owners didn't want to eat them anymore.
When I was in Hanoi in 2010, in the central districts as unrural as you can get in Vietnam, skinned dog carcasses were hanging at a number of markets. If westernization has had an impact, it must be more recent than that. I’m curious to go back and see for myself.