In a blender combine the first seven ingredients (through cayenne pepper); reserve the squeezed lime. Cover and blend about 1 minute or until smooth. Strain mixture. If desired, cover and chill up to 4 hours. If chilled for more than 1 hour, blend again before serving.
Wet the rims of shot glasses or small serving cups halfway around with the reserved squeezed lime. Dip the rims into Mint Salt to coat lightly. Fill glasses with yogurt mixture. If desired, garnish with fresh mint and sliced cucumber.
In a mortar or a small bowl combine salt and mint. Crush with a pestle, a muddler, or the back of a small wooden spoon until the mint is thoroughly incorporated into the salt.