Juice the Ruby Red Grapefruit (2) and reserve the juice.
Zest and slice the other Ruby Red Grapefruit (1/2) zest and slices aside.
Fill a cocktail shaker with ice. Add Casa Noble® Tequila (4 fluid ounce), grapefruit juice, Simple Syrup (2 fluid ounce), and Orange Liqueur (0.5 fluid ounce). Stir until mixed and chilled, about 30 seconds.
Combine the grapefruit zest, Granulated Sugar (2 tablespoon) and Salt (1 tablespoon) on a plate. Take a grapefruit slice, and run it along the edges of the glasses. Dip edges into zest mixture to fully coat.
Strain the margarita mixture while pouring into the glasses with Ice (to taste). Serve with a slice of grapefruit, and enjoy!