Steakhouse Tomato Salad

In a jar with a tight-fitting lid, combine olive oil, cider vinegar, ketchup, sugar, paprika, and Worcestershire sauce; season with coarse salt. Shake well to combine.

Arrange tomatoes and onion on a serving platter, alternating tomato and onion slices. Drizzle with some of the dressing; serve immediately with remaining dressing on the side.