How to Make It
In a medium bowl, toss the celery and carrots with 1 teaspoon each of the salt and sugar. Add the vinegar and gently squeeze the vegetables with your hands to work in the seasonings. Let stand for 5 minutes. In another bowl, toss the cucumbers with the remaining 1 teaspoon of salt; work the salt into the cucumbers. Let stand for 5 minutes.
Rinse the celery, carrots and cucumbers under cold water and squeeze dry. Transfer the vegetables to a large bowl.
In a medium saucepan of boiling salted water, cook the shrimp just until pink and curled, about 1 minute. With a slotted spoon, transfer the shrimp to the bowl with the vegetables. Add the squid to the water and cook until opaque, about 1 minute; transfer to the bowl.
In a mortar, pound the garlic to a paste with the chiles and the remaining 1 tablespoon plus 1 teaspoon of sugar. Stir in the fish sauce, lime juice and water. Add the dressing to the bowl and toss well. Sprinkle the peanuts over the salad and serve.