Clicking https://www.messenger.com/t/xxxxxxxx will take you to a bot and continue the conversation, if there was no conversation it'll begin it's 'firstRun' sequence.
Is it possible to create links that will execute a specific dialog and pass in data? It should ignore previous dialog state/stack and start a new stack with the specified data as argument to that dialog.
This is not possible. The url is used to identify the user/bot in messenger. The bot doesn't see the url so it can't read from it.
I would suggest taking a different approach. You could let the user pass in the code instead of adding it to the url.
There is a new functionality in Messenger platform that allows you to send specific messages to a bot: https://developers.facebook.com/docs/messenger-platform/referral-params I haven't tested it yet, but it may help you.
