Salmon is fully cooked when the color turns from translucent to opaque (usually white). The U.S. food and Drug Administration (FDA) suggest cooking to an Internal Temperature of 145 degrees F.

2 large salmon fillets
Zest and juice of 2 to 3 limes
1 tablespoon chopped fresh thyme leaves*
1 teaspoon coarsely ground black pepper
1 teaspoon coarse or coarse sea salt**
1 to 2 tablespoons extra-virgin olive oil (depending on size of fillets)
1 lime for finish
Coarse or Sea salt

** The coarse salt or sea salt is fabulous on the salmon.

BRINE:  2 1/2 tablespoons plain salt (without iodine) to 1 cup water.

Rinse the salmon steaks in cold water. Prepare a salt-water brine of 2 1/2 tablespoons plain salt to 1 cup of water, using approximately 1 quart of water; heat to just lukewarm. Add salt and stir until dissolved. Add warm salt water to approximately 4 quarts cold water (I use my sink as a bowl for this step). Place salmon, skin side down, in brine at for 20 minutes (make sure the fish is entirely covered by the brine).

After 20 minutes, gently remove salmon from brine and lightly rinse both sides with cold water to remove all traces of salt; gently pat dry with paper towels. Let salmon air dry on wire racks for at least 2 hours (this causes a "pellicle" - a tacky glaze on the fish to form. This indicates that it is ready for the smoking process).
 

Prepare your smoker according to manufacturer's directions.

I have an electric smoker and I like to use either alder or cherry wood. Smoking temperature of your smoker should be between 200 to 225 degrees F. (no higher). The easiest way to help keep the temperature low, is to almost close down the vents. Do not open or raise the lid of the smoker any more than you absolutely need to (it reduces the temperature inside every time you do). Monitor your temperature of your smoker during the smoke time.
 

Smoking the Salmon:

Place salmon fillets (skin side down) on sheets of aluminum foil and cut the foil around the fillets approximately 1/4-inch bigger (this keeps the fillets from sticking to the racks in the smoker). I also spray the racks with vegetable oil (makes for easier cleaning).

Grate the zest from the limes then squeeze the juice. In a small bowl, combine lime zest, lime juice, thyme (or other herbs), pepper, salt and olive oil; stir to mix. Rub the seasoning mix on the salmon fillets; coating them well.

Place salmon fillets (with the aluminum foil) on the oiled smoker rack. Smoke until a meat thermometer registers an internal temperature of 140 degrees F. in thickest part of salmon (salmon will be slightly opaque in thickest part). Remember the salmon continues to cook after it is removed - you don't want an overcooked and dried out salmon. I prefer a moist salmon and not dried out.) Remove salmon fillets from smoker.

Cut extra lime in half and squeeze over cooked salmon fillets. Sprinkle lightly with more coarse salt. Serve salmon either warm, cool, or chilled (refrigerate until ready to serve). If making ahead, cover airtight and refrigerate up to 3 days.