Place cherries, sugar, and water in a medium saucepan. Simmer for 4 minutes. Using a slotted spoon, remove the cherries and set aside.
Dissolve 2 Tbsp cornstarch in 2 Tbsp cold water. Bring the syrup to a boil and stir the cornstarch mixture into the boiling juice, stirring as it thickens. Add salt, lemon juice, lemon rind, and cherry liqueur. Cook, stirring occasionally for 7 minutes.
Return the cherries to the syrup and cook for 3 minutes more. Remove from heat and pour into a sterile jar. Syrup may be stored for up to 2 weeks in the refrigerator.