Preheat oven to 425 degrees. Rinse and trim your chicken thighs. Pat them dry and set aside.
Combine the paprika, oregano, garlic powder, onion powder, cumin and salt in a small bowl and mix. Evenly distribute the spice mix on both sided of your chicken thighs and place them on a sheet pan.
Cut the tops off your Garlic heads and peal away the outer skin and place them on the sheet pan.
Slice one of your lemons in ¼ inch slices (you should get about 5-6 slices depending on the size of your lemons) and add them to the sheet pan along with your drained artichokes. Drizzle the whole pan with your oil, making sure you get plenty on the garlic and chicken.
Rinse and dry the parsley, coarsely chop and sprinkle over the sheet pan when it is done. Bake for 20 minutes. Take the sheet pan out of the oven and add your tomatoes, olives and another drizzle of oil, and return to the oven for another 15 minutes.
When serving your chicken, squeeze out the pulp from the garlic cloves and serve alongside the tomatoes, artichokes and olives. Slice your remaining lemon in wedges and squeeze over your chicken.