Shellie's green bean and potato salad

During my week off, I visited Shellie back home. She made this amazing salad and I couldn't get enough of it. The dressing had lime in it, which was unexpected. I've only seen vinegar and lemon as acids for dressings, and associate limes with Mexican food and sweets. The lime is tangy like lemons (I love tangy and sour flavors), but it's more subtle.

Below is a very loose recipe. Adjust the recipe for as little or as much as you'd like.
-Waxy potatoes
-Green beans
-Red onions, finely sliced

Dressing
-Limes, juice and zest too, if you want (it makes the whole dish much more fragrant)
-Clove of garlic
-Squeeze of Dijon mustard
-Olive oil
-Rice wine vinegar
Boil the potatoes until soft and drain. Boil green beans about seven minutes (or so they are cooked but still crunchy) and drain. Mix in the red onion and dressing while the potatoes and beans are still warm.

Notes:
-To give you an idea of yield: I boiled about a pound of potatoes and half a pound of green beans, sliced a quarter of a red onion. It was enough for a bowl for dinner and a square Tupperware for lunch the next day.

-I tried it with both baby red potatoes and fingerlings. I definitely prefer the fingerlings. They have a more creamy texture and absorb the dressing a lot better than the baby reds.

-I made a whole lot last last weekend... After a week, the beans and onion do get limp, but it still tastes good.