In a large bowl, mix olive oil, harissa paste, clementine juice and minced garlic cloves.
Add in the chicken thighs and stir well to make sure all pieces are covered with the marinade.
Cover with a plastic wrap and put the bowl in the refrigerator. Marinade for 2 to 24 hours.
Heat the grill pan over medium heat.
Place the chicken thighs on the grill pan and don't move them for about 5-8 minutes depending on their size.
Once cooked on one side, flip the harissa chicken and cook them on the other side for another 5-8 minutes.
Serve warm with saffron couscous.