Pour water in a small pot; add sugar and strawberries.
Bring to a boil; reduce to a simmer to soften the strawberries.
Using a small bowl, dissolve cornstarch in water; pour into strawberry mix and bring to a boil; stirring constantly; mixture will be slightly chunky.
Remove from heat; cool completely.
Using a hand mixer, on medium speed, beat cream cheese, heavy cream, powdered sugar, lemon zest and vanilla for 2 minutes until it thickens.
Chill in the refrigerator for 30 minutes.
Remove from the refrigerator and transfer to a piping bag.
Fill the taco shells with cream cheese filling and top with 1/2 tsp. strawberry filling.
Sprinkle with additional graham cracker crumbs, if desired.