How to Make It
Set a resealable plastic bag in a bowl and add the vinegar, sugar and 2 tablespoons of salt. Bring a large saucepan of salted water to a boil. Add the scallions and cauliflower and blanch until crisp-tender, about 1 minute. Using a slotted spoon, transfer the vegetables to the plastic bag. Add 2 cups of cold water. Seal the bag, pressing out the air; freeze for 15 minutes.
Meanwhile, add the snap peas to the boiling water and blanch until bright green, about 1 minute. Drain and cool under running water. Pat dry and cut diagonally into 1-inch pieces.
Drain the scallions and cauliflower, reserving 3 tablespoons of the pickling liquid. Transfer the vegetables to a large bowl. Add the snap peas, white beans, ham, parsley and sunflower seeds. In a small bowl, whisk the reserved pickling liquid with the olive oil and season with salt and pepper. Pour the dressing over the salad and toss well. Serve right away.