Whenever you interact with a smart contract, even if the transactions that you send are not linkable to an identity, you still need to pay the fees of the contract with a normal tz{1,2,3} address. One way to work around that is to set up an injection service that will send the transaction on your behalf in exchange for a small fee that you can add inside the shielded transaction (so that the service doesn’t learn your tz address).

The service can still learn your IP address, that sometime is even more sensitive than your tz address, so to solve that you can provide the service as a hidden Tor service.

We are planning to build this as simple website to inject the transaction that can be reached through tor.

We are not planning to run the service ourselves but just to provide the tech.