Set a medium saucepan on the stove. Add 1 3/4 cups water and 1/2 teaspoon of the salt, and bring it to a boil over high heat.

Add the bulgur to the boiling water in the saucepan and stir once. Lower the heat to low, cover the pan, and cook for 12 minutes, until the water is absorbed and the bulgur is tender.

Put the thinly sliced red onion into a small bowl. Add about 1 tablespoon of the lime juice and a small pinch of the remaining salt, toss, and set the bowl aside so the onion can soften.

Drain the black beans in a colander and rinse them under cool water. Shake off the extra water and set the colander aside.

Set a large skillet over medium heat and add the olive oil.

Add the chopped red onion to the skillet and cook for 3 to 4 minutes, stirring now and then, until it looks softened and a little glossy.

Add the frozen corn to the skillet. Cook for 4 minutes, stirring a few times, until the corn is hot and lightly browned in spots.

Sprinkle the chili powder and cumin into the skillet. Stir for about 30 seconds, just until the spices smell toasty.

Add the black beans and 1/4 cup water to the skillet. Add 1/4 teaspoon of the salt, stir, and cook for 3 to 4 minutes, until the beans are hot and the liquid in the pan lightly coats them.

Put the Greek yogurt, crumbled feta, lime zest, the rest of the lime juice, the remaining salt, and the black pepper into a small bowl. Stir until creamy, then add 1 to 2 tablespoons water if needed so the mixture loosens into a spoonable sauce.

When the bulgur is done, take the saucepan off the heat and leave it covered for 2 minutes so the grain can finish steaming.

Uncover the saucepan and fluff the bulgur with a fork. Stir in half of the chopped cilantro.