Rinse the chana dal thoroughly under running water until the water runs clear.
In a large pot, heat the oil over medium-high heat.
When the oil is hot, stir in the tomatoes, ginger, chilies, cumin seeds, dried chilies, asafetida, turmeric, and amchur. Cook for 3-4 minutes until the tomatoes start to break down and the spices become fragrant.
Add the rinsed chana dal, methi, cilantro, and water. Bring it to a boil over high heat. Once boiling, return to medium heat, and cook covered for 50-60 minutes, until the dal is tender.
In the meantime, prepare the tadka (tempering). In a separate small pan, heat the coconut oil over medium heat. Add the mustard seeds. Sauté until the seeds start to sizzle, pop, and release their aroma.
Lower the heat and add the chili powder, curry leaves, and black salt. Stir-fry the spices for a minute or until fragrant. Turn off the heat and set the tadka aside.
After the dal has cooked for 50-60 minutes and is tender but not completely mushy, add salt to the dal and continue cooking with the pot covered, stirring occasionally, another 15-20 minutes until the dal is falling apart just a little bit. Add water if the dal is looking too thick for your taste.
Once the chana dal is cooked to your desired doneness, pour the prepared tadka over it and gently stir to combine, allowing the flavors to meld together.
Serve in attractive serving dishes and garnish with cilantro, and if desired freshly sliced red or green chilies.