Drop the potatoes into a small pot of boiling water and cook until fork tender, around 10-20 minutes depending on the size of the dice. Remove the potatoes with a slotted spoon and allow them to cool. You can cook the potatoes in advance and cool them in the fridge, or you can drop the potatoes into a bowl of ice water to hurry the cooling. Or, add warm potatoes, that's yummy too.
Whisk the dressing together in a cup with a fork. Thin with water if needed.
Gently toss everything together.
Sprinkle with green onions and add salt and pepper to taste.
The potatoes and asparagus can be cooked in advance and added cold to the salad for an even quicker meal.
This is written up as a single serving because I tend to make this just for myself, but feel free to batch cook and scale this recipe up.