Line a small glass baking dish with plastic wrap, overhanging wrap on both sides by about 8 inches. 

Wrap 2 small, heavy weights like unopened food cans in foil. Set aside. 

Stir together sugar, salt and 3 tablespoons of peppercorns. 

Sprinkle a thin layer over the bottom of the prepared dish. 

Slice salmon in half so you have two even pieces.

Lay one piece skin-side down in dish, and sprinkle with another layer of sugar mixture. 

Lay the dill on top, and sprinkle with 2 tablespoons of the vodka (if using) and another layer of sugar mixture. 

Finally top with the remaining salmon, skin-side up, and sprinkle with remaining sugar mixture and vodka. 

Fold plastic wrap over the top to seal the salmon in. 

Cover top of dish with another layer of plastic and put weights on top.

Refrigerate, turning salmon over every 12 hours, for 2 to 3 days. 

Unwrap salmon, discard dill and rinse fillets quickly under cold water to remove peppercorns. 

Pat dry with paper towels. 

Slice salmon very thinly on the bias, angling your knife so it cuts along (not through) the skin. 

Serve the slices sprinkled with some of the reserved peppercorns on squares of cocktail bread, crackers, blinis, cucumber slices or endive leaves.

Safety Note: There is a risk of contracting parasites from eating raw or cured fish, so those with special health concerns should always speak with a doctor before doing so.