Place a 3 1/2-quart heavy-bottomed pot over medium heat. Add 3 tablespoons of oil to the pot and then the onions. Season the onions with salt. Cook the onions, patiently, until they begin to brown and become deeply colored. Stir them often enough that the onions on top brown at the same pace as those on bottom. Don’t do this too fast; you want melted, gooey onions, not seared onions. Take your time; it takes a while.
Once the onions are browned to your liking, add the garlic. Once you smell the garlic, add the turmeric, curry powder, cumin, and cayenne pepper. Give it a stir then add the tamarind, tomatoes, chickpeas, and ginger. Reduce the heat and let the sauce simmer. Taste the sauce for salt and adjust as necessary.
Cook the noodles.
Once the noodles are done, drain them, and put them on a platter. Top the noodles with the chickpea stew and top with green onions or cilantro or both. Serve.