In a measuring cup, combine the remaining 1 teaspoon salt with the sugar and vinegar. Put the celery, carrots and onion in 3 separate bowls. Toss each vegetable with 1/3 of the vinegar mixture. Let stand for 5 minutes. Remove the vegetables and squeeze dry. Put them in a large bowl. Add the cucumber, pork, shrimp, 1/4 cup of the coriander and 2 tablespoons of the mint. Add the Nuoc Cham Dipping Sauce and toss well.