what are the approximate minimum dance floor dimensions to dance tango argentino? I need it for a project of tango argentino-themed restaurant/club.
Pretty much depends on the number of people you want to accommodate. Tango Argentino is a slowish dance with moderate progression and room coverage, so you can get away with quite a bit less than the "120m² per 6 dance pairs" requirement I seem to remember from ballroom dancing tournaments. But a tango argentino-themed restaurant/club will most certainly also want to accommodate milongas and tango waltz. What does "themed" mean? Do you only want enough room for show dancing, or are the patrons themselves permitted to dance?
How about contacting some of your prospective customers and ask them what made them pick their favorite locations so far? You'll want to accommodate them in more respects than just floor area anyway.