Spicy Grapefruit Margarita
Mix tequila and chiles in a large pitcher. Let steep 3 hours, or longer if a spicier tequila is desired. Discard chiles. DO AHEAD: Can be made 1 month ahead. Cover; chill.
Pour enough water onto a small plate to cover. Pour enough salt onto another small plate to cover by 1/4". Dip rims of eight 12-ounce glasses into water, then into salt to lightly coat; fill with ice. Add grapefruit juice to pitcher with tequila. Fill with ice; stir until cold. Divide drink among glasses.
Cactus Fruit Cocktails
Place the prickly pears in a blender and pulse until liquefied. Strain the juice into a small bowl (you should have about 1 cup of juice).
Fill a large cocktail shaker with ice, add the prickly pear juice, tequila, triple sec, lime juice, and sugar and shake vigorously.
Pour into glasses filled with ice, rimmed with salt or sugar, if you like. Garnish with lime slices.
Variation: For a fancy party cocktail, combine some chipotle chile powder with your coarse-grained salt before rimming the glasses. The smoky, spicy salt will make a nice complement to the sweet, fruity drink.
Blackberry-Poblano Margarita
In a cocktail shaker, muddle the blackberries and poblano peppers. Shake with the tequila, Cointreau, and ice. Strain into a martini glass.
Note: If working with fresh blackberries, raspberries, or blueberries, to avoid pulp or seeds in your glass, strain before serving. Blackberries not in season? Use frozen berries.