In an 8×8 baking dish or bowl, whisk together smoked paprika, turmeric, cumin, cinnamon, 2 tsp pepper, 1 tsp salt, 1/4 cup lemon juice, 1/2 cup olive oil, red pepper flakes and minced garlic to make the marinade.
Add the chicken breasts and sliced onion to the marinade, toss to coat thoroughly, cover and refrigerate for at least 1 hour.
Preheat the oven to 425°F (220°C).
Place the marinated chicken and onions in the baking dish (arranged in a single layer if possible) and bake uncovered until the chicken is browned at the edges and cooked through, about 40–45 minutes.
Optional: for crispier top, broil on high for 2–3 minutes at the end—watch closely to avoid burning.
Remove chicken from the oven and let rest 5–10 minutes, then slice.
Meanwhile, bring 2 cups water to a boil in a small pot. Add 1 cup bulgur, cover, reduce heat and simmer about 5 minutes or until water is absorbed; stir occasionally. Let bulgur cool.
In a large bowl, combine the cooled bulgur with 1/4 cup olive oil, 1/4 cup lemon juice, chopped tomatoes, chopped cucumber, green onions, parsley, mint, 1/4 tsp salt and 1/4 tsp pepper; toss to combine.
To assemble, spread the tabbouleh on a large shallow plate, arrange sliced chicken on top, add sliced avocado, Kalamata olives and sprinkle with crumbled feta. Serve with pita and hummus.