You can turn the filet over after about 18 hours, again making sure the exposed skin is covered with salt.
Notes to answer questions:
1. It’s unlikely that you will have much in the way of anything left over from this production. If you do, just wrap the skin around the flesh, cover the whole thing in plastic wrap, and store in the fridge. Or pop it back into the glass dish with the lid. It’s best if you eat it up within two or three days. The longer you’ve cured it, the longer it will last.
2. I have never frozen the cured salmon, because there is never that much left over, but I imagine it would be just fine, as our Norwegian friend Astrid in the comments says.
3. A lot of fish sold in the supermarket has already been frozen when it is sold as “fresh.” Freezing kills any parasites. You can ask when you buy it if it has been frozen. If it hasn’t and you are worried, just freeze it, thaw it in the fridge, and then proceed. I usually wash my filet before curing it, but the salt will kill any surface bacteria.
*It cracks me up when people advise you to use a ziploc bag or wrap the fish well in plastic or somehow make this super complicated in a way that has you ending up with a lot of yucky drippy plastic. Just use a glass dish and cover it.