Are AR wallets/addresses created automatically for miners, and if so, how do I access them?

[JamesPiechota]

Yes, if you do not provide a wallet address on the command line when starting the miner, a new wallet will be created for you and stored in the ‘wallets’ directory. When you run the miner again, you will want to pass the generated wallet address on the command line. Any valid Arweave wallet address will work for mining.

For more information see Node Wallet