Preheat grill or grill pan over medium-high heat until extra hot.
Halve the peaches and remove the pits. Cut one of the halves into wedges. Halve one jalapeno. Place on hot grill and cook until desired char, about 4 minutes.
Place the peaches and jalapeno into a blender and add the juice of one lemon, the simple syrup, and tequila. Blend on high for at least a minute or until desired consistency.
Place in the fridge while you get the glasses ready.
Moisten the rim of each glass with a cut lemon. Dip into margarita salt. Add several cubes of ice to the glass.
Once the peach mixture has cooled, pour into each glass.
Take the charred wedge and skewer onto a skewer. Place in drink and garnish with an additional sliced jalapeno.