Bring 1 cup water to a boil in a kettle or small saucepan for the couscous.

Put the dry couscous and 1/2 teaspoon of the salt into a large heatproof bowl.

Pour the boiling water over the couscous. Drizzle in 1 teaspoon of the olive oil, cover the bowl with a plate or lid, and let it sit for 5 minutes.

Squeeze the juice from one lemon half into a small cup. You need about 2 tablespoons of juice. Cut the remaining lemon half into wedges for serving.

Put the Greek yogurt and chopped roasted red peppers into a small bowl.

Add 1 tablespoon of the lemon juice, 1 tablespoon of the olive oil, and 1/4 teaspoon of the black pepper to the yogurt bowl. Stir until the sauce is evenly mixed, then set it aside.

Put the drained tuna into a medium bowl.

Add the remaining 1 tablespoon lemon juice, 1 teaspoon of the olive oil, and half of the chopped parsley to the bowl with the tuna. Flake the tuna with a fork and stir gently so it stays in soft pieces.

Heat the remaining 1 tablespoon olive oil in a large skillet over medium heat.

Add the drained chickpeas and the ground cumin to the skillet.

Cook the chickpeas for 4 to 5 minutes, stirring a few times, until they are hot and lightly browned in spots. Sprinkle in the remaining 1/4 teaspoon salt and a few grinds of black pepper.

Uncover the couscous and fluff it with a fork so the grains separate.