Soak the dal (peas) in plenty of water for at least 1 hour. Drain and coarsely grind in a blender without adding any extra water.
Finely chop the onions, chilies, ginger, and curry leaves. Mix the all the ingredients except the oil together to make the vada mix.
Heat a thick bottomed pan and add enough oil to cover the bottom of the pan at least 1/2 inch deep. Make lemon size balls of the vada mix. When the oil seems hot enough take the balls one by one flatten each into a disc and place in the hot oil. Let it cook for a couple minutes until the sides begin to brown. Flip and cook the other side .
Drain and serve.
Notes
Fry in batches and do not crowd the pan.
The beans of choice are split chick peas or pigeon peas (Toor dal or Chana dal). You can use either or a mix of both.
Asagoetida is available in stores selling Indian spices
Do not use asafoetida if yo are allergic to gluten - though in its pure form it does not contain any gluten , wheat is usually added to prevent it from caking.