Small Spaniard, possibly, or a native of Omsk? (8)
I believe the answer is:
siberian
'a native of omsk?' is the definition.
(Omsk is a city in Siberia)
'small spaniard possibly' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'spaniard possibly' becomes 'iberian' (Spain is a country on the Iberian Peninsula).
's'+'iberian'='SIBERIAN'
'or' acts as a link.
(Other definitions for siberian that I've seen before include "Of far eastern Russia" , "Russian" , "from part of Russia?" , "From east Russia" .)