Build the Aromatic Base: In a large Dutch oven or heavy-bottomed pot, heat the avocado oil over medium heat. Add the chopped onions and cook, stirring frequently, for 7 to 9 minutes, until softened and translucent. Stir in the minced garlic and grated ginger, cooking for another 2 minutes until fragrant.
Bloom the Spices: Add the black mustard seeds, ground turmeric, smoked paprika, ground coriander, garam masala, and cayenne pepper to the pot. Stir constantly for 60 seconds to toast the spices and release their aroma.
Create the Tomato Foundation: Add the chopped Roma tomatoes and the fine sea salt. Stir well, scraping any flavorful bits from the bottom of the pot. Cook for about 5 minutes, allowing the tomatoes to break down into a thick paste.
Combine and Simmer: Add the rinsed red lentils, no-salt-added vegetable broth, and water. Stir to combine. Increase the heat to bring the mixture to a simmer, then reduce heat to low, cover, and cook for 25 to 35 minutes. The lentils should be completely soft and the dal should have a thick, stew-like consistency.
Finish and Serve: Uncover the pot and stir in the fresh lime juice. If the dal is too thick for your liking, add a splash of hot water until it reaches your desired consistency. Ladle the warm dal into bowls, top generously with fresh cilantro, and serve immediately with lime wedges on the side.