Make the Pickle: In a small saucepan, combine rice vinegar, sugar, and salt over medium heat. Stir until dissolved. Remove from heat immediately and pour over the julienned carrot (and daikon if using) in a bowl. Let sit for at least 10 minutes while you prep the rest of the salad.
Prepare Vegetables: Wash and dry your lettuce and cabbage thoroughly; excess water will dilute your dressing. Shred the cabbage finely. If using cucumber, slice it thinly. Place all chopped vegetables (excluding avocado) in a large mixing bowl.
Drain Pickles: Drain the pickled carrots well using a fine-mesh sieve or paper towels. You want them moist but not dripping wet. Add them to the salad bowl along with the cilantro and cucumber.
Whisk Dressing: In a separate small bowl, whisk together peanut butter, hoisin sauce, soy sauce, lime juice, sesame oil, garlic, and sriracha until smooth. Slowly add warm water, one tablespoon at a time, whisking constantly until the dressing reaches a pourable consistency similar to heavy cream.
Combine: Pour about half of the dressing over the salad. Toss gently but thoroughly with tongs to ensure all leaves are coated. Taste and add more dressing if needed. The salad should be glossy but not swimming in liquid.
Serve: Divide among bowls. Top with diced avocado, crushed peanuts, fresh mint, and a squeeze of lime juice just before eating to preserve the brightness.
