Wash jalapenos and remove stem.
Cut in half and then cut in half again.
If you want the powder to be less spicy, remove the pith and seeds from half of the jalapenos.
Set dehydrator to ~145F. Put jalapenos on the trays and ensure none are overlapping.
Dehydrate overnight or for 16+ hours.
The next day, remove 1 from the dehydrator and allow to cool. Once cool, bend it, it should snap if it's dry enough. If it still feels pliable, it needs to keep dehydrating.
Once dry, grind in a spice grinder or pestle and mortar into a fine powder.
Combine in a bowl 1/2 cup of Diamond crystal kosher salt and 2 tbsp of the Jalapeno powder. Mix well.
Store in a non-reactive container or storage bag and use at a later date.