Combine spices and 1 teaspoon salt; season chicken on both sides with all but 1/2 teaspoon of the spice mixture.
Working in batches, grill cutlets, 2 at a time, in a grill pan over medium-high heat, until browned, 3 to 4 minutes. Flip; reduce heat to medium. Grill until cooked through, about 2 minutes.
Prepare couscous according to package directions. Meanwhile, cook garlic and ginger in oil in a large skillet over medium-high heat until fragrant and just golden, about 30 seconds. Stir in 6 cups spinach, the raisins, reserved 1/2 teaspoon spice mixture, 1/4 teaspoon salt, and the water. Cook, stirring occasionally, for 15 seconds; push to side of skillet. Add remaining 6 cups spinach. Cook until wilted, about 1 minute. Slice chicken, and serve over spinach with couscous and yogurt.