In a blender or food processor, pulse the jalapeños until finely minced. Add the cilantro and pulse until chopped. Add the remainder of the ingredients and blend/process until mixture is smooth and completely puréed. Adjust seasonings to taste, adding more salt and pepper if necessary. Cover and refrigerate for at least 4 hours, but preferably longer. Serve with tortilla chips or vegetable dippers.
Individual jalapeños can vary in their heat levels. That being said, as a general rule:
For a mild dip, scrape out and discard the seeds & membranes from your jalapeños.
For a medium dip, leave the seeds & membranes intact in one jalapeño and scrape them out/discard from the second jalapeño.
For a spicy dip, leave all of the seeds & membranes intact. Or you can even add an additional jalapeño for extra heat, if that's your preference.
This dip will slightly thicken after chilling in the fridge for several hours. However, it is not intended to be (and will never turn into) an overly thick dip.