01 - Whisk together olive oil, minced garlic, ground cumin, smoked paprika, dried oregano, ground coriander, salt, black pepper, and lemon juice in a bowl. Add chicken breasts and coat thoroughly. Refrigerate for at least 15 minutes, up to overnight for deeper flavor development.
02 - Heat a grill pan or skillet over medium-high heat. Cook marinated chicken breasts for 5 to 6 minutes per side until golden brown and cooked through. Remove from heat and let rest for 5 minutes, then slice into strips.
03 - Bring chicken broth or water to a boil in a saucepan. Stir in couscous, cover tightly, and remove from heat. Let stand for 5 minutes, then uncover and fluff with a fork.
04 - In a small bowl, whisk together tahini, yogurt, lemon juice, olive oil, grated garlic, salt, and pepper. Gradually add warm water while whisking until achieving a smooth, drizzling consistency.
05 - Divide prepared couscous among four bowls. Arrange a bed of spinach or arugula on top. Add sliced chicken strips, cherry tomatoes, cucumber, red onion, Kalamata olives, and feta cheese if using.
06 - Drizzle each bowl generously with the lemon-tahini sauce. Garnish with fresh chopped parsley. Serve immediately while chicken and couscous are warm.