Rinse lentils with water until the water runs clear. This will remove any extra dust or starch left.
Turn on Instant Pot to saute mode and add olive oil.
Add cumin seeds, garlic, and serrano pepper to pan and allow seeds to simmer (once oil is hot this should only take about 10 seconds).
Add chopped onion and allow to brown.
After about 3 minutes, mix in the dry spices. Then add the tomato.
Allow this mixture to cook for another minute.
Mix in the water and lentils.
Turn on the manual pressure on high and cook for 6 minutes. (7 minutes will make for a bit mushier lentils).
Once it's complete, allow it to sit for 10 minutes before manually releasing the pressure.
Mix it up and top with cilantro and lime juice, or serve as it is. Serve alongside roti, naan, or basmati rice.