Combine sugar and cornstarch, mixing well. Drain the cherries and reserve 3/4 of the cherry juice. In a saucepan, stir the reserved cherry juice into the sugar and cornstarch mixture. Cook over medium heat until thickened. Remove from heat. Gently stir in cherries and almond extract, and pour into a 9"x12 baking dish.
Mix the oatmeal, sliced almonds, and brown sugar. melt the butter and stir it into the oatmeal mixture, mixing until crumbly, Sprinkle topping over fruit mixture.
Bake at 350 ° F. for 50-60 minutes (until topping is browned).