For the Harissa-Apricot Paste, combine all ingredients.
For the chicken and marinade, combine and chill several hours or overnight.
Heat a tagine bottom or Dutch oven over medium to medium-high heat with EVOO, two turns of the pan, and brown the chicken skin-side down first about 6 minutes on each side, working in 2 batches to avoid crowding pan.
Remove browned and crispy skinned chicken to a plate. Add leeks, onions, crushed garlic to the chicken drippings and let soften with salt and pepper. Add Harissa-Apricot Paste and stir, cover with the lid and allow to sweat about 3 minutes. Remove the lid and stir in tomato paste and add stock or bone broth. Let the liquid come up to a simmer, about 5 minutes. Add couscous and chickpeas, stir and nestle the chicken back into the pan, bring back up to a simmer and cover. Let cook for 15 minutes at a simmer.
To serve, add the juice of 1 lemon and top with herbs.