Here are a few threads on cold smoked salmon.
There are a few ways to do this and they all work well. Try different methods to see what's to your liking.
First and the easiest method
Wet brine: Use about 1/2 lb of salt per 3 qts of water and a handful of brown sugar. To check your salinity a raw egg should float in this solution. If not add more salt.
Brine the salmon for at least 1hr/ 1/2 inch of thickness. I will brine an average side of skin on salmon for 6 hours. Better to over brine than under brine. If the skin has been removed the brining time can be shorter. You will not get a firm texture like you get in dry brining but the fish will firm up a bit. Dark brown sugar in the brine will darken the color of the fish and IMO is a good thing.
The fish should be rinsed well after brining, dried and a pellicle allowed to form. Passive method is to put it on a rack or tray in the fridge and let the surface get tacky. I have also used a fan which will form a pellicle in an hour or two.
Dry curing: This method which commonly used to make gravlax can be used. A dry cure of salt, sugar and any aromatics can be made and the fish is covered in this cure, wrapped in cellophane, weighted and refrigerated ~ 24 hours. I have done it as little as 12 hours with good results. This will pull out a lot of water from the fish and will result in a firmer texture. The thin tail portion is at risk of becoming drier and more salty as compared to the wet brine. In making gravlax the fish is then rinsed, dried and sliced but cold smoking takes it to the next level.
Combo of dry and wet brine: You can do a mixture of dry cure followed by a wet brine. This will give you the firmer texture but then by wet brining will soften the texture a little.
I personally like the wet brine since I like the silky texture of the fish that results. Others like a more firm texture so it's a personal choice. Wet brining is also easier for me since I just mix it up in a big plastic container and toss it in the fridge. No wrapping or weighing down needed.
http://www.smokingmeatforums.com/for...ad.php?t=73705
http://www.smokingmeatforums.com/for...ad.php?t=79447
http://www.smokingmeatforums.com/for...highlight=NOva