In a large sauce pan on medium heat, cook greenbeans to desired doneness or al dente (firm to the bite) Rinse in a cold icebath to stop the cooking and keep them green.
In a large mixing bowl; add red onion, garlic,olive oil, red wine vinegar, salt, and pepper to taste. Add cooked green beans.
Place the bowl in the refrigerator for about 4 hours to marinate and chill the garden fresh green bean salad.