Mix cornstarch with cold water in a small bowl and put aside. 

Combine frozen cherries, sugar, and salt in a medium saucepan and cook over medium-high heat. Stir frequently to dissolve the sugar and release cherry juices. Bring pan to a boil, then lower heat to a simmer. Cook about 5 minutes until the cherries are soft and the liquid has thickened slightly.

Stir cornstarch into the saucepan and simmer for another minute, remove from heat. 

Stir in lemon juice and allow to cool completely.

Place cream cheese in a bowl and beat with electric mixer on medium-high until fluffy, about 3 minutes. 

Add condensed milk, sour cream, vanilla, and salt. Beat until very fluffy.

Transfer to a shallow bowl and smooth out, topping with cooled cherry sauce.

Sprinkle crushed graham crackers on top and serve with wafer cookies, pretzels, or graham crackers for dipping.