Whisk together the lemon zest, lemon juice and Dijon in a large mixing bowl. Slowly stream in the olive oil while whisking continuously. Season with salt and pepper. Roughly tear the lettuce into another large bowl and add the herbs. Drizzle half the dressing along the sides of the bowl (not directly on top of the salad), then gently toss everything to coat in the dressing. Taste for seasoning here, adding additional salt and pepper if needed. Serve immediately.
A really nice addition is adding 1 tablespoon of rinsed, chopped capers to the dressing.