Heat the oven to 200 C / 400 F.
Pat the chicken thighs dry with paper towels. Season both sides with the smoked paprika, salt, and black pepper.
In a mixing bowl, toss the chickpeas, cherry tomatoes, red onion, olives, garlic, oregano, and lemon zest with 2 tbsp olive oil, 1/2 tsp salt, and 1/4 tsp pepper. Spread the mixture evenly over a 13 x 18-inch / 33 x 46 cm sheet pan.
Nestle the chicken thighs skin side up on top of the chickpea mixture, pressing them in slightly. Drizzle with 1 tbsp olive oil and tuck the lemon slices around the pan.
Roast for 35 to 40 minutes, until the chicken skin is deep golden brown and an instant-read thermometer inserted into the thickest part of the thigh (away from the bone) reads 165 F / 74 C.
Pull the pan out and scatter the feta over the top. Return to the oven for 5 minutes, just until the feta softens.
Let the pan rest for 5 minutes. Sprinkle with parsley and serve warm straight from the pan.