Prepare the glasses: Run a lime wedge around each glass rim, dip in coarse salt, and fill with ice. Set aside.
Make peach puree (if using fresh peaches): Peel and pit 1-2 ripe peaches. Blend until smooth. Strain if you want it extra silky.
Combine ingredients: In a cocktail shaker, toss in ice, tequila, triple sec, lime juice, peach puree, and agave syrup.
Shake well: Shake hard for 15-20 seconds. You’ll know it’s ready when the shaker feels frosty.
Strain and serve: Pour the mix into your prepared glasses. Top with peach slices and a lime wedge.
Want it frozen? Just blend everything with 2 cups of ice instead of shaking. Pour and enjoy that slushy goodness.