Hi @mtcore,
Good catch! Adminer isn’t in the public beta quite yet but it’s on our list of things to add. See “What’s Next” here: Local Lightning Public Beta
In the meantime, you can connect to the database with other clients such as Sequel Pro (macOS) or HeidiSQL (Windows).
To connect to a Local Lightning site’s database, copy the details from the site’s “Database” tab in Local and then enter it into Sequel Pro or HeidiSQL. On macOS, you’ll want to connect using the socket. On Windows, connect using the IP and port.