Cook the lentils, kidney beans + water in the instant pot (you can also do this in a slow cooker or on the stovetop, the cook time will just be longer). In the Instant Pot, cook on high pressure for 30 minutes, natural release.
Mash some of the lentils + beans using a potato masher. Add in the baby spinach and let the dal simmer on “keep warm” setting while you make the spice mixture.
To make the spice mixture (masala), heat a medium pot over medium heat.
Add coconut oil, onions, garlic ginger paste (or minced garlic/ginger), and cook until the onions are translucent.
Add the crushed tomatoes and cook through – about 5 minutes. Add the spices and salt. Cook about 3 minutes more.
Add in the lentils/kidney beans/spinach mixture into the large pot. Stir to combine and simmer for 20 minutes, uncovered, on medium low heat. Add water if the dal is getting too thick.
Add the coconut milk and let it simmer for another 10 minutes until combined.