In a pan add 1 tsp oil..after heat up add finely chopped onions,tomato and capsicum and saute them for few sec..
Now add little salt and mix well..
Now add sweet corns,tomato ketchup,1 tsp vinegar and 2 tbs dressing(any of urs choice)and mix them throughly..
Now at last add lettuce..quickly mix and Switch off the flame..
Take out in a bowl and serve at room temperature..