How to Make It
In a small bowl, combine the chopped red onion with the vinegar and a pinch of salt. Let stand for 10 minutes.
Meanwhile, in a small bowl, cover the capers with warm water and let stand for 10 minutes. Using a slotted spoon, transfer the capers to a work surface and finely chop them.
In a medium bowl, combine the olive oil with the lemon juice, lemon zest, garlic, parsley, chervil, tarragon and chives. Drain the onion, squeezing out any excess vinegar, and add to the bowl along with the capers. Mix well and season with salt and pepper. Let the salsa verde stand for at least 1 hour before serving.