Spiced Dal with Fluffy Rice and Salted Yogurt

Name: Spiced Dal with Fluffy Rice and Salted Yogurt
Ingredients: 2 tablespoons ghee, virgin coconut oil, or vegetable oil; 1 medium yellow onion, finely chopped; 1 2-inch piece ginger, peeled, finely grated; 2 garlic cloves, finely grated; 1½ cups red lentils (masoor dal), rinsed; 2 teaspoons ground coriander; 1 teaspoon ground turmeric; ½ teaspoon ground cardamom; Pinch of crushed red pepper flakes; Kosher salt; 1 lime; 1 small red onion, very thinly sliced into rounds, rinsed; Pinch of sugar; ½ cup plain whole-milk Greek yogurt; Cooked Jasmine or basmati rice (for serving); Freshly ground black pepper