Preheat oven to 400°; place 2 large pieces of foil on sheet pan + oil the foil; add one fillet onto one side of each + spread each fillet with 1-2 tbsp sauce, ½ cup tomatoes, 1 tbsp oil + salt/pep; fold empty side of foil over ingredients; working from one end, tightly fold edges of foil creating a sealed half-moon shape

Bake 12-15 min til tuna is firm, opaque + cooked through

Meanwhile, boil large pot of salted water, add ½ the bag of couscous + stir; cook 5 min, then drain; add to a large bowl, drizzle on 1 tsp oil + season with salt/pep; divide to plates

Open foil packs by cutting a slit through center (watch out for steam!) + divide to plates