You can just create a new wallet on Counterwallet.io, and then add 2-3 addresses in it, and then click on each address and show & copy the private key. The address itself is public key.
There’s also a counterwallet-helper (on this forum) which is Python based client to generate addresses in the same order, using the Counterwallet-style 12 word pass phrase.
I didn’t suggest to use Counterwallet because the danger is you may use a CW address number 1, for example, in ZeroNet, and later forget you did that.
Now if you send some crypto to your first address and you forget about your ZN setup, someone might get hold of your private key for that address and sweep it…
I guess you can label your address “ZeroNet” to remind yourself to not use that address for funds, but that label is kept only until Counterwallet server is reinstalled (usually until the next version) and it’s not cross-server.
Anyway, you can use a CW address for this, just don’t forget there’s a risk that it may get leaked in case of ZN bugs or your setup errors, etc. Maybe create a ZN-only Counterwallet wallet and don’t use it for anything but ZN.