Bring water to boil in the pot. Add the soba and reduce the heat so the water is simmering, not at a hard boil. Cook until soft and pliable, but not mushy. Drain and add very cold water back to the pot, add some ice if necessary. Stir the noodles with your hands or long chopsticks to loosen any remaining starches. Drain again and run cold water over the noodles until the water runs clear.
Whisk together lime juice, soy sauce, ginger, honey, and sesame oil in a large bowl. Add the zucchini, carrots, scallions, and avocado chunks and toss to combine. Season with salt and pepper.
Serve immediately at room temperature with cilantro for garnish.