Chop the tomatoes in medium sized pieces.
Add the mung beans (moong dal) to the pressure cooker and dry roast in low heat for about 3 to 4 minutes or until the raw smell is gone.
Add all spices, mix well and heat for another 1 minute.
Add the fresh tomatoes and green chili and saute for another 1 minute.
Add salt and water, mix everything well. Make sure the lentils are not sticking to the bottom of the pan, or else it will get burnt.
Close the pressure cooker with lid and safety valve in place and cook in medium heat for about 8 to 10 minutes after the steam comes or cook until 2 whistles. Make sure to follow all directions in the manual while using pressure cooker.
After 8 to 10 minutes of cooking, switch off the pressure cooker and wait for it to cool down.
Once the pressure cooker is cooled, you can open and see if the lentils are cooked and soft.
You can gently mash the contents of the cooker using a ladle and mix everything well.
If you prefer more liquid like consistency for the moong dal sambar, you can add little more water at this point and heat for a minute. (If you prefer to mash the dal separately or if you want to mash the dal much more you should use the traditional way of cooking the dal separately. As I already mentioned above, this is a quick and easy way of making the lentils and vegetables together in pressure cooker, so we are fine with the little lentils which are not mashed so perfectly. Either way, this is so delicious!)Now let us make the seasoning for the moong dal sambar we just made.