I think there's a few reasons.
One, their system is excellent and they pressure the puck carrier into poor shooting areas and tight spaces along the boards where turnovers and clears and more likely to happen. They also play a very aggressive style at the blue line in limiting zone entries, and they have a lot of forwards who have very good active sticks.
Two, they play duos on the PK so their penalty killers always know where their partner is and what they're going to do. That predictability just further builds on their structure.
Three, Skinner is a big goalie who can usually make the first save if he's set and if the team limits a lot of east to west movements through the slot, and they play to Skinner's strengths while limiting his weaknesses.