Serve this salad with grilled meats; it's especially great with spare ribs.
Discard outer leaves from cabbage. Quarter cabbage and core. Cut quarters crosswide into 1/4-inch-thick slices. Wash cabbage well in a large bowl of cold water and spin dry. In a large glass or stainless-steel bowl toss together cabbagge and salt until salt is dissolved, about 5 minutes. Transfer cabbage to a colander set over a bowl. Drain cabbage 1 hour. Rinse cabbage well and squeeze in small handfuls until dry as possible. (Note: I have never done this elaborate cabbage prep. I think rinse it well, salt it lightly, let it sit a bit.) Seed and mince chiles. (Note: I never bother to seed chiles. This does, of course, make it hotter.) Discard outer leaves of lemongrass and trim root end. Separately mince garlic, shallot and lower 2 inches of lemongrass.
In a large bowl toss together cabbage, chiles, lemongrass, garlic, shallot, fish sauce and lime juice. Salad may be made 2 hours ahead and chilled, covered. Serve salad at cool room temperature.