Grind coriander and cumin seeds in spice mill or with mortar and pestle to a powder. Heat 1 Tbsp. oil in a large skillet over medium-high. Add onion and cook, stirring frequently, until soft and beginning to brown, about 5 minutes. Add ginger and garlic and cook, stirring, until fragrant, about 1 minute. Add coriander, cumin, turmeric, and cayenne and cook until mixture starts to stick to bottom of skillet, about 1 minute. Add potatoes and remaining 1 Tbsp. oil and toss to coat. Add 1/2 cup water and scrape up any bits in bottom of skillet. Stir in tomatoes and their juices and salt. Bring to a simmer, breaking up tomatoes with a wooden spoon. Cover and cook, adding more water by the tablespoonful if necessary, until potatoes are tender, 2025 minutes. Stir to combine (its okay, and kind of preferred, if some of the potatoes get a little smashed here). Add eggs, turn to coat in sauce, and simmer until warmed through, about 5 minutes. Divide curry among bowls and top with cilantro and yogurt. Serve with rice or naan.