Put the honey on a small plate. Combine the salt and cayenne pepper on a second small plate. Dip the rim of a rocks glass into the honey and let any excess drip off. Dip into the salt and cayenne mixture to rim the glass. Set aside.
In a cocktail shaker filled with ice, combine the tequila, lime juice, Honey Syrup and bitters. Shake, then pour the contents of the shaker into the rimmed rocks glass. Garnish with a slice of lime.
Combine the honey and 1/2 cup water in a small pot and stir together. Bring to a simmer over medium heat, then remove from the heat and let cool completely.