Drain syrup from cherries into a 2-cup measure; add water to make 1-1/2 cups. (Save cherries for Step 3.)
In a small pan, blend a few tablespoons cherry syrup into cornstarch until smooth; stir in remaining syrup, mustard, molasses, tabasco and salt. Cook over low heat, stirring constantly, until mixture thickens and boils 3 minutes.
Stir in cherries and lemon juice; heat slowly just until bubbly.