I'm breaking apart a mesh for texturing, via a series of Primitive extractions from a Principal Mesh.

Its easy enough to select the right Primitives and use the Extract Tool- but I would like to Delete the Original Primitives at the same time, how can I use the same Primitive Selection to Extract a new Mesh, and Delete the old selected Primitives?

Having to Re-select the Primitives adds double work and I would like to avoid that if possible.

Just copy that list of numbers that appear in the Group1 field of the Extract and paste it into a Delete node.

From what I can tell, however, the Extract already removes all other non-selected primitives because it creates a new object and only merges in those primitives you have selected.

Try setting your 3D viewport mode to Hide Other objects you might just be seeing the ghosted remains of the original object.