First, chop together a small onion and scallion and put them in pot with tomato paste, olive oil, harissa (a Tunisian spice paste), some spices to taste (cumin perhaps) and chickpeas.
You'll let it boil for a while, and then add meat if you're choosing to use any. Because it was Eid yesterday, this couscous was very different from any I'd had before, because rather than making it with chicken or meat, we used a Tunisian Eid speciality called 3osben. 3osben is made with the innards of the sheep by creating pouches with parts of the stomach and filling it with spinach and other parts of the innards. I've included a picture of the 3osben and also one of it added to the sauce.
Next you're going to start with your couscous. Start a sort of double boiler--basically, the couscous is cooked by the steam from the sauce below.
Then, add couscous to the second level of the pot and cook uncovered over the sauce.
Cook for a while, and then remove the couscous from the steam and add a little water to it in a bowl. Mix thoroughly! Then you'll add your veggies to the sauce mixture and replace the couscous on top of it in the double boiler. After boiling for a while, add a hot pepper if you desire!
You know the sauce is ready when you see oil floating on the top. Then, you'll remove the couscous from the double boiler and, in a large bowl, add some of the tomato mixture (make sure not to get any veggies or meat in this part).
Display in a nice serving dish, put your meat and veggies on top, and voilà! You've made Tunisian couscous.