The Dominion DVDs are now up for pre-order in Spain, to be released on Mar 20, 2015.
It’s unclear whether the show will also be released on Blu-ray in Spain, so far amazon.es does not seem to list a Blu-ray edition. There is no word on the extras on this release yet, but since the language and subtitle tracks are the same as on the UK edition, we can only assume that the Spanish DVDs will have the exact same content as the UK DVDs (i.e. the episodes plus the deleted scenes and gag reel).
CAVE: The discs may be region-coded for Europe only (region 2). The good news is that Universal Home Entertainment is known for not region-locking most of their releases. At the moment we don’t have any way of knowing for certain whether there is a region lock for the Dominion discs.