Place the kosher salt onto a small shallow dish. Rub a slice of grapefruit around the rim of the glass then roll the glass in the kosher salt. Place the grapefruit and lime wheels against the inside of the glass and fill with crushed ice.
Add the grapefruit juice, lime juice, chamomile citrus simple syrup, tequila and club soda to the glass. Stir to combine and serve immediately.