Put the salt, pickle brine, and dried dill weed in a food processor.
Pulse a few times until everything is incorporated.
The salt will be slightly wet from the brine. Spread the salt out on a baking sheet and let dry either in a warm oven or overnight. It might stick together a little, but you can easily break it up with your hands when dried to store.
Pour the salt into a container for storing. The flavors will continue to build over time. Place a pinch of dry, uncooked rice in the container to help keep it from caking and to absorb moisture.
Notes
It is best to use a small food processor to ensure the blade can reach the ingredients, although a larger one will still work.I love to use jars like this to store the flavored salts in, but you can also use empty spice containers. These jars would fit approximately half of one batch of salt.