Roughly chop the herbs to make it easier to blend.
Place avocado, lime juice, water, jalapenos (if using), herbs, oil and salt in a tall jug or glass jar. Just make sure the mouth is wide enough for your stick blender. Or pop in the bowl of your food processor.
Using your stick blender or processor, blitz until everything is combined and the herbs are finely chopped and flecked prettily through the sauce.
Taste and season with more salt, lime juice or oil if needed (it probably won't).