In a large bowl, toss chicken, coriander, paprika, red pepper flakes, cinnamon, 3/4 tsp salt, and 1/4 tsp black pepper.
In a large high-sided skillet over medium heat, heat 2 tbsp oil. Add half the chicken and cook until golden, 2–3 minutes per side. Transfer to plate. Repeat with 1 tbsp oil and remaining chicken.
Wipe out dark bits from pan. Add garlic and 1 tbsp oil. Cook 30 seconds until fragrant.
Stir in broth, orzo, and 1/2 tsp salt. Bring to boil, then reduce heat and simmer 12–14 minutes until orzo is tender and most of liquid is absorbed.
Stir in dill and return chicken to skillet.
In a medium bowl, toss cucumber, tomatoes, feta, lemon juice, and remaining 1 tbsp oil with pinch of salt.
Top chicken and orzo with cucumber salad and more dill before serving.