Where can I find a domain registered on-chain?

OpenSea

You can view your domain (and everyone else's) on our OpenSea page - https://opensea.io/collection/3dns-powered-domains

If you're wallet is connected, you can filter to the domains that you own.

Etherscan

The Optimistic Etherscan contract can be found here - https://optimistic.etherscan.io/address/0xbb7b805b257d7c76ca9435b3ffe780355e4c4b17