I was looking up the Vietnamese word cửa hàng. Hàng Seems fairly straight forward as it used to be written with the Chinese character 行 and pronunciation is quite similar also. Cửa is not as simple; it seems to be a form of 𨷶 (or perhaps 𨷯) but there is very little info about it.
Wiktionary does say that it is a:
举 and 门 makes me think that it's got something to do with being 'open' (i.e.: for business) but I'm not sure.