Methods

1. To prepare the chilies, remove and discard the stems. For thinner chilies, like Indian long, slice in half lengthwise. For fatter, thicker peppers, like jalapeno and Fresnos, cut in half, remove and discard the seeds and ribs, and cut lengthwise into ¼-inch strips. (If you want a hotter achaar, you can leave the seeds and ribs in some or all of the chilies.) Place the cut chilies in a bowl, toss with 1 tablespoon fine sea salt, and let sit at room temperature for at least 2 hours, up to overnight. Transfer the salted chilies onto a clean kitchen towel, discarding any liquid that’s accumulated in the bowl, and arrange them into a single layer on half of the towel. Fold the other side of the towel over and press to remove as much excess moisture as possible.
2. Place the coriander seeds, fennel seeds, fenugreek seeds, black mustard seeds, black peppercorns, cloves, and cinnamon stick in a spice grinder and pulse into a medium-coarse powder, 15 to 20 pulses. Transfer the ground spices to a bowl along with the remaining 2 teaspoons fine sea salt, turmeric, and the cut chilies, and toss to combine. 
3. Heat the untoasted sesame oil in a small saucepan over medium heat until almost smoking. Pour over the spiced chilies mixture, stir, and let cool to room temperature. Transfer to a clean jar, making sure to push down the chilies so they are submerged in the oil, and place in a cool, dry place until the chilies soften and ferment to your desired level of funkiness, 2 to 4 days, depending on the temperature. Transfer to the refrigerator and store for up to 6 months, making sure whenever you use some of the achaar, the chilies are covered by a thin layer of oil.