Pat chicken dry and season with kosher salt, be sure to season under the skin too. If you have the time, arrange the chicken on a tray or a shallow dish and chill in the fridge uncovered for a few hours or overnight (optional.)
Place the chicken in a large zip bag. In a small bowl, combine spices (oregano, black pepper, coriander, paprika, and cumin.) Add the spices to the chicken in the bag.
Add the garlic, onion, lemon zest, lemon juice, and olive oil. Zip the bag shut. Toss chicken around and massage to make sure it is well coated in the marinade. Let the chicken marinate for about 30 minutes, or if you have the time, refrigerate for 2 to 4 hours.
When ready, heat the oven to 450 degrees F.
Lightly oil a baking dish and arrange the chicken drumsticks (yes, include the onions and the marinade). Arrange lemon slices in between.
Bake for 35 minutes or until the chicken is fully cooked and its juices run clear (internal temperature of chicken should register 165 degrees F using an instant read thermometer). If you like, broil for just a few minutes until skins are crispy to your liking.
Cook's Tip: For best flavor, allow the chicken legs to marinate in the fridge for 2 to 4 hours, or 30 minutes at room temperature.
Prepare ahead tip: To save time, you can absolutely work ahead (one night in advance) on this chicken legs recipe. One of the things I like to do is prepare the chicken and allow it to marinate in the fridge overnight, that way, it's ready to bake after a long work-day. It helps to take it out of the fridge for a bit before baking so it's not too cold and so it cooks more evenly.
Leftovers: If you have leftovers, let chicken cool completely before storing in airtight container. Refrigerate for 2 to 3 days. If you want to freeze the cooked chicken drumsticks, place them in a freezer bag and put them in for up to 6 months. Thaw before re-heating.