Prepare the couscous according to package instructions. Meanwhile, in a bowl, combine the flour, curry powder and 1/2 teaspoon salt. Add the chicken and toss to coat.
In a large nonstick skillet, heat 1 tablespoon olive oil over medium-high heat. Add the chicken and cook, turning once, until browned and just cooked through, 5 minutes. Transfer the chicken to a plate.
Add the remaining 1 teaspoon olive oil to the skillet and heat over medium-high heat. Add the onion and sliced celery and cook, stirring, for 3 minutes. Add the cherries and 1/2 cup water and bring to a boil. Stir in the evaporated milk and chicken along with any juices; season with salt. Serve over the couscous and top with the celery leaves.