In a cocktail shaker, add the rhubarb and the strawberry, and muddle. Add the tequila, agave nectar, lime juice and some ice and shake. Strain into an ice-filled 12-ounce Collins glass that has been rimmed with salt. Top with the grapefruit soda and a pinch of salt.
This is a very cool cocktail. I am taking the Paloma cocktail to next level. Paloma is a classic in Mexico made with tequila, very easy to drink and very easy to make.