Fill a cocktail shaker or small pitcher with ice cubes. Add the gin, vermouth, tomato water, vegetable juice, and a healthy squeeze of lemon juice. Add a couple drops of Pernod if desired--it adds a nice background flavor, but more than 1 or 2 drops will overpower the drink. Season with salt, pepper, and a dash of hot sauce.
Cover and shake vigorously until mixed and chilled, about 30 seconds. (In general, the drink is ready by the time the shaker mists up.) Strain into a chilled cocktail glass. Add the olive, tomato, and onion garnish. Drink.
1 (28-ounce) can tomatoes
1/2 teaspoon kosher salt
Puree the tomatoes and their juices with the salt and a pinch of sugar. Line a small sieve with a coffee filter and set over a bowl. Pour the tomato into the sieve and set aside to strain, about 3 hours. Discard the solids and save the tomato liquid. Refrigerate until ready to use.