First, cook the fingerling potatoes. I like to keep them whole while cooking, but you can also slice the potatoes in half before cooking.
Place the fingerling potatoes in a large pot and fill with enough water so potatoes are covered with about 1 inch of water on top. Then, generously salt the water.
Bring the potatoes to a boil, then reduce to a simmer. Simmer for about 8- 10 minutes, then check the potatoes by gently piercing with a knife. The potatoes should give a little, yet still be semi-firm and al-dente. If needed, cook an additional few minutes, checking with a knife until they are cooked through but not soft or crumbly. Please keep in mind that potatoes sliced in half before cooking will cook faster.
Strain the cooked potatoes and set them aside to cool completely before slicing.
While the potatoes are cooling, dice the veggies including the red onion, scallions, and dill. Set aside for later.
Add the dressing ingredients to a large bowl including olive oil, lemon juice, dijon mustard, garlic powder, salt, and pepper. Then, whisk together until smooth.
Then, add the chopped veggies & dill to the bowl and gently mix to coat with the dressing. Next, slice the potatoes into half or quarters and add them to the bowl. Gently mix together until the potatoes are all coated with the dressing.
You can enjoy the bowl of potato salad right away, but I recommend covering it with plastic wrap and storing it in the fridge for about 1 hour before serving. This allows the potatoes & veggies to soak up the flavors of the veggies. Once chilled, serve and enjoy!