How to query large list and retrieve one field of all items?

Image a list with i.e. 20.000 list items. All items have the field ContainerId (indexed). I now want to retrieve all ContainerIds to do other stuff with those.

SPQuery is limited to a maximum of 2000 items - yet the ViewFields is pretty much what I want. Is it still the best was to go forward? How would I implement paging I didn't see a Skip field for the query.

Any better way to go forward? In the end I want to have a List<string> allContainerIds.