Turn on a multi-functional pressure cooker (such as Instant Pot(R)) and select Saute function. Heat olive oil; add onions, garlic, ginger, and cumin. Cook until tender, about 2 minutes. Combine moong dal lentils, water, coriander, salt, garam masala, cayenne pepper, and turmeric in a multi-functional pressure cooker (such as Instant Pot(R)). Close and lock the lid. Select high pressure according to manufacturer's instructions; set timer for 15 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer's instructions, 10 to 40 minutes. Unlock and remove lid. Stir in lemon juice and cilantro.