Combine 2 tablespoons each smoked salt and sugar on a plate. Rub the rims of 4 glasses with an orange wedge, then dip into the salt mixture. Fill the glasses with ice; add a pinch of smoked salt to the ice and swirl to combine. Combine 1/2 cup each Campari, gin and sweet vermouth in a liquid measuring cup; pour into the glasses. For garnish, char 4 wide strips of orange peel, one at a time, over a flame using tongs; drop 1 into each glass.