In a large skillet over medium heat, roast the jalapeños and unpeeled garlic until soft and blotchy brown, 15-20 minutes.
Cool, then peel the garlic and roughly chop the jalapeños. (you can remove some of the seeds, to control heat)
Combine the garlic, chiles, and lime juice in a blender and pulse to finely chop.
Turn blender on and slowly dribble in the oil.
Pour into a small bowl and add a tablespoon or two of water to thin the salsa.
Taste and add salt, about a teaspoon.
Best consumed within the first 24 hours. Can be kept in the fridge for a day or two, re-blend if it starts to separate.
