Making the pineapple-cilantro syrup: To a blender, add the pineapple, water and sugar. Puree for 1 minute, adding a little more water if needed, to keep things moving. Pour into a pitcher or bowl, add the cilantro and stir to blend. Refrigerate overnight, then strain through a fine mesh sieve.
Making the chile salt: To a food processor, add the fleur de sel, chile and sugar. Process until the mixture forms a fine pink powder.
Making the cocktail: Dip the rim of a martini glass in water, then in the chile salt. To a cocktail shaker, add 5 ice cubes, 2 ounces of the vodka and 2 ounces of the pineapple-cilantro syrup. Shake vigorously, and strain into the chile salt-rimmed martini glass. Serve immediately. Repeat with the remaining ingredients.