Warm Arugula, Olive and Tomato Salad

A really nice salad to accompany dinner.  From Food and Drink Spring 2015.

1/4 cup olive oil
1/4 cup red wine vinegar
2 tsp Dijon mustard
2 cups grape tomatoes
1 cup thinly sliced red onion
1/4 cup chopped, pitted dry cured black olives
2 cloves garlic minced
4 cups packed arugula
Salt and freshly ground pepper
6 cups torn romaine lettuce hearts

• Whisk together 2 tbsp of the oil, the vinegar and mustard in a small bowl; set aside.
• Heat remaining 2 tbsp oil in a large skillet over medium high heat.  Add tomatoes, onion and olives and sauté for about 3 minutes or until onion is softened.  Add garlic and sauté for 1 minute or until fragrant but not browned.
• Pour in vinegar mixture, then add arugula.  Stir just until arugula is wilted, for about 1 minute.  Remove from heat and season to taste with salt and pepper.
• Divide romaine lettuce equally between individual salad plates, the top with warm tomato mixture.