Can I change my solid axle New Hub into a quick-release?
Yes. Our hubs use widely available non-proprietary threaded axles. You can get a quick-release (hollow) axle to replace a solid axle on your Surly hub, or vice-versa. Ask at your bike shop. Tell them you need a 9x1mm thread pitch axle of the appropriate length for the front or a 10x1mm thread pitch axle of the appropriate length for the rear. The hardware (cones and whatnot) will swap over easy with the right tools and knowhow. Have a shop do it if you are not versed in this sort of behavior. If you know your way around a hub, get a 15mm and a 17mm cone wrench and you'll be in business.
If you have an OLD hub of ours that is silver or black and says "1x1" on it, you have an old beast with a proprietary axle that cannot be replaced (because it is not made anymore.) You are screwed. If your hub is red and says "1x1" then it's off of our 11th anniversary 1x1 from a year or two back and they act just like our New Hubs, so the above paragraph about easily available axles applies.