Peel all the lemons, making sure not to leave too much pith (white part) which is bitter. If you see there is a lot of pith you can use a small knife to shave it off the peels. This task takes a while, but it makes a better result.
Place the lemon peels in your dehydrator or oven. Set it to the lowest temperature.
Dehydrate until the peels break easily when you break it in half. You might need to take it out of the dehydrator to cool before you do this.
It is best to then condition the peels by placing the cold peels in a jar and shaking them every day for 3 days. If the peels are not dry enough, they will clump together. This means the peels are not ready to blend. Please read the post for full explanation.
Once they have been conditioned, place the peels and peppercorns into a high-powered blender or coffee grinder. You may have to do this in several batches.
Lastly, add salt and blend again. You can have the seasoning as chunky or as smooth as you like. I like it as a happy medium.