Bring large pot of salted water to a boil.
Scrub potatoes and cut into 1/4 inch slices.
Cook potatoes about 15-20 minutes till fork tender.
Meanwhile mix dressing in medium mixing bowl.
Combine olive oil, lemon juice, Dijon mustard, red wine vinegar, garlic, parsley, thyme, 3 tbsp. dill weed and salt, pepper to taste.
Whisk a minute or two until thoroughly combine.
Drain potatoes well and place in large serving bowl, along with chopped red onion.
Pour vinaigrette over potatoes and onion and gently combine.
Top with remaining dill weed.
Serve immediately or can store covered in fridge for up to five days.