Being too heavy handed with dressing can turn a salad very limp very fast - start with a small amount to begin with, toss the ingredients - and then decide if you need a little more.
1/4 cup olive oil
1 tbsp fish sauce
2 tbsp lime juice
1/2 to 1 tbsp soy sauce
A little chopped fresh chilli
1-2 tsps palm sugar or raw sugar
1 tsp grated ginger
This is good added to a mix of shredded Chinese cabbage, shredded carrot, shallots, cucumber, fresh mint and coriander or Thai basil (toss in some chopped nuts and cooked, cooled noodles for more substance).