Rinse salmon with water; pat dry with paper towels.

Lay a piece of plastic wrap onto a flat surface. Mix together kosher salt and sugar in a small bowl. Pour 1/2 of the salt mixture onto the plastic wrap; lay salmon on top. Cover salmon with remaining salt mixture.

Fold plastic wrap around salmon until secure; cover with a second layer of plastic wrap.

Transfer to a 9x9-inch baking pan; cover with an 8x8-inch baking pan. Place a heavy object onto the smaller baking pan to weigh salmon down. Cure in the refrigerator until salmon’s surface is silky, about 48 hours.

Fill a large bowl with ice water. Fill a second bowl with cold water and 3 drops liquid smoke.

Unwrap salmon and dip in liquid smoke mixture to rinse. Remove to ice water and let sit, submerged, for 30 minutes. Repeat rinsing and submerging 2 more times, adding 3 drops liquid smoke to ice water each time.

Dry salmon with paper towels. Slice with a sharp knife, starting at the thin edge.