If you have time, toss the diced eggplant with a teaspoon of the salt in a large colander. Set the colander over a bowl or in the kitchen sink to drain for at least 30 minutes. No need to rinse. If you are in a rush, you can skip this step.
When eggplant is ready, set the Instant Pot to SAUTE mode and give it a couple of minutes to heat up. Add the 6 tablespoons of sunflower oil and let heat a minute more. Add the 2 diced jalapeños, tablespoon of ginger, 1 minced garlic clove, and the 1/4 teaspoon of mustard seeds. Fry until the garlic becomes golden, but not burnt, about 4-5 minutes.
Add the 1 1/4 pounds diced potatoes, diced eggplant, the remaining 1 1/4 teaspoon salt, the 1/2 teaspoon cinnamon, 1/2 teaspoon turmeric, 1/4 teaspoon fennel seeds, 1/4 teaspoon garam masala, and 1/4 teaspoon lime zest. Toss to coat in oil. Add 1/2 cup water and 2 tablespoons lime juice, stir to combine, scrape the bottom of the Instant Pot well when adding the water to get any stuck on bits. Seal with the Instant Pot lid.
Set Instant Pot on high pressure for 4 minutes. Let natural release for 15 minutes then manually release the remaining pressure. Or you can let it naturally release the whole time if you have the time.
Taste and adjust the flavor with more salt or lime juice or both or even an extra pinch of garam masala. Transfer to a serving dish and sprinkle with cilantro. Enjoy!