Make the dressing: Combine all dressing ingredients in a blender and run until smooth, scraping down sides once. You can also hand-whisk the ingredients in a bowl, but be vigorous so the chunky ingredients smooth out. Taste and adjust ingredients to your preference.Assemble the salad: Holding back a little of the peanuts, scallion, and herbs for garnish, add all ingredients to a large bowl and toss with half of the dressing, adding some or all of the remaining dressing to taste. Season with salt and pepper, if needed. Sprinkle with reserved peanuts, scallions, and herbs for extra prettiness. Eat right away or bring it somewhere wonderful in a cooler and eat it in a few hours. Do ahead: The dressing and chopped vegetables (except the cilantro, which might wilt faster), stored separately, will keep for up to 5 days in the fridge.