According to Eris, the planet had been offered entry to the Dominion because the Dominion believed that the telekinetic powers of its inhabitants would be useful to them. When the natives had refused, the Jem'Hadar came in and seized control. They took over the communications center and executed the leaders.
This planet was only mentioned in dialogue.
StarTrek.com suggested that perhaps these natives of Kurill were called, Kurillians, with the episode making no mention of it and Eris simply presenting herself as being from Kurill Prime.
According to Star Trek: Star Charts (p. 71), Kurill Prime was the homeworld of the Vorta. This Class M world was where the Changelings discovered the Vorta as the small, timid, ape-like forest dwellers. They originally were living in hollowed-out trees to avoid predators. Changelings genetically engineered the Vorta into intelligent humanoids and employed them at the highest level of the Dominion, as the story was told in "Treachery, Faith and the Great River".