Yes, you can (and should) make salad in a mortar. When hardy vegetables, like cabbage, are lightly crushed in a tall Thai-style clay mortar with a long wooden pestle, they are tenderized just enough to yield a pleasing soft crunch.
Using a kruk, pound ginger, garlic, chile, and sugar to a fine paste, 1 to 2 minutes. Add cabbage and herbs; pound until cabbage is slightly softened and crushed and flavor of herbs is released, about 30 seconds. Add fish sauce and lime juice, and toss with pestle and a spoon until evenly combined. Let mixture stand at room temperature 15 minutes. Serve salad topped with peanuts and fried shallots.