Heat the oil in a wide nonstick skillet. Add the chile and onion and cook over medium heat, stirring occasionally, for a few minutes or until the onion turns translucent. Next add the greens with the water clinging to their leaves. Sprinkle with 1 teaspoon salt and cook until wilted, turning them with a pair of tongs after 3 or 4 minutes. Puree with the drained yogurt, then transfer the mixture to a large skillet. Turn the heat on low to warm the yogurt. Don’t get it too hot or it will curdle.