1. Heat oil in a medium saucepan over medium-high heat. Add curry powder and garlic to pan; cook 1 minute, stirring constantly. Add quinoa and 2 cups water; bring to a boil. Cover, reduce heat, and simmer 16 minutes or until tender. Remove from heat; stir in salt. Cool completely.
2. Add mango and next 4 ingredients to cooled quinoa; toss gently.
3. Combine cucumber, mint, and yogurt in a small bowl; stir well. Divide spinach evenly among 6 plates, and top each serving with about 3/4 cup quinoa mixture and about 2 tablespoons raita.