Chrissy's Sweet 'n' Sour Tomato Salad

From: AllRecipes

An easy to prepare, delicious sweet 'n' sour tomato salad
   just right to compliment any meal - or eat alone! Prep
   Time: approx. 30 Minutes. Ready in: approx. 30 Minutes.
   Makes 6 servings.

7 tomatoes
1 small yellow onion
1/2 cup white sugar

1/2 cup distilled white vinegar
1/2 cup vegetable oil
salt and pepper to taste

Directions
1 Thinly slice the tomatoes. Cut the onion in half
   through root end, then thinly slice into half-circles. In a
   large bowl, toss together tomatoes, onion, sugar, vinegar,
   oil, salt and pepper. You may adjust the amounts of
   vinegar and sugar according to your taste. Serve at room temperature.