Add 2 ounces of tequila, 1/2 ounce of Aperol, 1 ounce of lime juice, 1/2 ounce of guava puree, and 1/2 ounce of agave syrup to a cocktail shaker.

Fill the cocktail shaker with ice cubes.

Shake vigorously until well-chilled, ensuring that all ingredients are thoroughly combined.

Strain the mixture into a salt-rimmed margarita glass filled with ice.

Garnish with a slice of fresh guava or a lime wedge, if desired.