Combine 3/4 cup water, 1/4 cup juice, 1/4 teaspoon curry powder, and 1/4 teaspoon salt in a small saucepan over high heat. Bring to a boil; gradually stir in couscous. Remove from heat; cover and let stand 5 minutes. Fluff with a fork.
Combine remaining 1/4 cup orange juice, remaining 1/2 teaspoon curry powder, remaining 1/4 teaspoon salt, olive oil, honey, and black pepper, stirring with a whisk. Stir 1 tablespoon dressing into couscous mixture, and set remaining dressing aside.
Combine chicken and remaining ingredients in a large bowl. Drizzle remaining dressing over salad; toss gently to coat. Serve salad over couscous.