Rub rim of an 8-oz. glass with a lime wedge; dip rim of glass in 1/4 tsp. Barbecue Rub to coat. Combine vegetable juice, lime juice, Worcestershire sauce, vodka, and 1/4 tsp. Barbecue Rub in a cocktail shaker; fill with ice. Cover with lid; shake vigorously until chilled. Strain into prepared glass filled with ice. Garnish, if desired.