Spread the sriracha very thinly on a baking sheet lined with parchment paper or a silpat (I prefer the latter).
Heat in the oven at 200 degrees for about 1 1/2 hours until completely dry.
Remove from the oven and cool.
Peel or scrape off the dried sriracha into a bowl. Gently grind to a powder in a small mini food processor or blender (I used my bullet for this step). Be sure to pulse while grinding.
Add the salt, lime zest, and lime juice. Crush with a mortar and pestle or pulse again to combine.
Spread the mixture back on the silpat in a thin layer and heat in the oven for another 1 1/2 to 2 hours until the mixture is dry. Remove from the oven and cool completely.
Pulse again or crush to salt consistency (using your bullet or mini food processor).