Set a medium saucepan on the stove. Pour in 1 3/4 cups water and bring it to a boil over high heat.

Set a large skillet on medium-high heat and add 2 tablespoons of the olive oil.

Put half of the sliced red onion into the skillet. Cook for 2 to 3 minutes, stirring often, until it starts to soften.

Add the cherry tomatoes, the cumin, and 1/2 teaspoon of the salt to the skillet. Cook for 6 to 8 minutes, stirring every minute or so, until many of the tomatoes split and their juices look saucy.

Add the black-eyed peas to the skillet. Stir well and cook for 2 minutes, until the peas are glossy and heated through.

Add the spinach to the skillet a handful at a time. Stir each handful in until wilted before adding the next. Cook just until all of the spinach is soft, about 1 to 2 minutes total.

Lower the heat under the skillet to low so the bean mixture stays warm without drying out.

When the water in the saucepan boils, stir in the couscous, the remaining 1 tablespoon olive oil, and 1/4 teaspoon of the salt. Cover the saucepan, take it off the heat, and let it stand for 5 minutes.

While the couscous stands, put the remaining sliced red onion in a small bowl. Squeeze in 1 tablespoon of lemon juice, add a small pinch of the remaining salt, and toss to coat. Let it sit to soften the sharp bite.

Put the feta, the Greek yogurt, 1 teaspoon of lemon zest, 1 tablespoon of lemon juice, and the black pepper in another small bowl. Mash and stir until the mixture looks thick and creamy with a few small feta pieces left.

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

Squeeze 1 tablespoon of lemon juice into the skillet with the black-eyed peas and tomatoes. Stir once and turn off the heat.