⅓–½ cup ((78–118 ml)) water, divided
To prepare the jalapeño chilies, trim away the stem end and cut in half lengthwise. Carefully remove and discard the seeds, leaving only the green chilies. Coarsely chop and measure ⅔ cup (about 60 g); reserve any extra for another recipe.
In a blender or small food processor, combine the chilies, cilantro, shallots, ginger, garlic, cumin, coriander and pepper. Add ⅓ cup (78 ml) of the water and process for 1 minute.
Stop to scrape down the sides and then continue processing, pulsing and stopping to scrape down as needed, until you have a fairly smooth, very well-combined puree. Add more water as needed to move the blades and transform chunky ingredients into a smooth paste or sauce.
Transfer to a jar, cover and refrigerate for up to 1 week, or freeze for 1 month.