Heat the oven to 400°F.
In a small saucepan over medium heat, bring 1/2 cup water to a boil. Remove from the heat, add the couscous, 1 Tbs. of the olive oil, and 1/4 tsp. salt. Stir well, cover the pan, and let sit for 5 min. Fluff the couscous with a fork and spread on a large plate to cool.
Meanwhile, season the steaks on all sides with 1-1/2 tsp. salt and a few generous twists of pepper. In a small bowl, mix the cumin, thyme, and 1 Tbs. of the mint and rub all over the steaks.
In a large bowl, season the tomatoes with 1 tsp. salt and a few generous grinds of black pepper. Add the couscous, parsley, scallions, and 1 Tbs. of the mint and toss. In a small bowl, whisk together the lemon juice and 3 Tbs. of the olive oil. Add to the couscous mixture and toss well. Taste and add more lemon juice if needed.
Heat a large cast-iron pan or a large, heavy ovenproof skillet over medium-high heat. When the pan is very hot (water spattered over the pan will immediately evaporate), add the remaining 2 Tbs. oil and the steaks; sear, moving them only to flip, for 2 min. on each side. Put the skillet in the oven and cook for about 5 min. for medium rare. Transfer the steaks to a carving board and let them rest for 5 min. before slicing them into thin strips. Sprinkle with the remaining 1 Tbs. mint and serve with the tabbouleh and pieces of warmed pita bread.
This dish calls for warmed pita bread. If you’ve got a couple of hours before dinner and you’re feeling inspired, make Homemade Pita Bread and grill in batches.