When we were in Mexico, we had a very similar drink to this one. For my birthday, my son recreated it, and we all decided I must share it on Just Salt It. 
 
Yield 1 cocktail 
 
Pear Simple Syrup
1½ cups water 
1½ cups pears, chopped into 1" pieces
¾ cup granulated sugar
2 cinnamon sticks
 
Cocktail
2 oz. Tequila
¾ oz. pineapple juice
½ oz. pear syrup
1 oz. lemon juice 
Tajin and a slice of lime for the rim 
 
Make the pear syrup by adding water, pears, sugar, and cinnamon sticks to a saucepan over medium heat. Stir gently until the sugar has completely dissolved. Turn the heat down and let it simmer for 30 minutes. Remove the syrup from the heat and let it sit for at least 15 minutes. Strain the syrup into a glass measuring cup and discard the pears and cinnamon stick. 
 
To make the cocktail, combine ingredients in a shaker with ice. Shake well and strain into a glass.
 
Cheers, and enjoy!