Step 1: Prepare the Prickly Pear Puree (if using fresh fruit). Wear gloves to handle prickly pears. Slice off the ends, make a lengthwise slit, and peel the skin. Chop the flesh and blend with 1-2 tablespoons of water until smooth.
Step 2: Strain the Puree. Pour the blended prickly pear mixture through a fine-mesh sieve or cheesecloth into a bowl, pressing firmly with a spoon to extract all the juice. Discard solids. (You should get about 1.5-2 oz of puree per fruit).
Step 3: Prepare Your Glass. If desired, moisten the rim of your serving glass with a lime wedge, then dip it into flaky sea salt or sugar spread on a shallow plate.
Step 4: Combine Ingredients. In a cocktail shaker, combine 2 oz Tequila Blanco, 1 oz fresh lime juice, 1 oz prickly pear puree, and 0.5 oz agave nectar.
Step 5: Shake. Fill the shaker two-thirds with ice. Secure the lid and shake vigorously for 15-20 seconds until the shaker is well-chilled and frosty.
Step 6: Serve. Fill your prepared glass with fresh ice. Strain the Prickly Pear Margarita mixture from the shaker into the glass. Garnish with a lime wheel or a slice of fresh prickly pear.