Combine the lime juice, simple syrup, lychees and their syrup and jalapenos in a cocktail
shaker and mash
with a muddler until the lychees are broken down. Bruise
with your hands, and add it to the shaker along with the tequila
. Fill the shaker with ice and cover and shake vigorously until very cold.
Pour the drink into a double rocks glass and serve immediately.