For the Dill Vinaigrette:
1 In a bowl, combine the olive oil, apple cider vinegar, lemon juice, dill, parsley, mustard, honey, garlic, red pepper flakes, salt and pepper. Whisk until emulsified. Taste for seasoning and adjust with salt, pepper, honey or vinegar as desired. Cover and set aside at room temperature until ready to serve. Leftovers can be refrigerated up to 5 days. Remove from the fridge 10 minutes before serving.
For the Scallion Chive Yogurt:
3 In a bowl, combine the yogurt, scallions and chives. Mix until well incorporated. Cover and refrigerate up to 5 days.
For the Smashed Potato Salad:
5 Add the potatoes to a pot and cover with water. Add the salt, set over high heat, bring to a boil and cook until the potatoes are just fork-tender, around 25 minutes. Drain the water and let the potatoes cool and evaporate, around 15 minutes.
6 Place a large heavy pan or griddle over medium heat. Add 1.5 tablespoons of olive oil and heat until shimmering. Carefully add the potatoes, working in batches if necessary, so as not to overcrowd the pan, and use the bottom of a measuring cup or press to gently smash until they’re around half-inch thick. Cook the potatoes, adding more oil as needed, until they’re golden brown and crispy, around 5 minutes. Flip the potatoes, drizzle with a small amount of the Dill Vinaigrette and cook until the bottoms are golden brown and crispy, around 5 more minutes. Transfer the potatoes to a tray and set aside.
7 Add the onions to the pan, raise the heat to medium-high and cook until lightly charred and caramelized, around 3 minutes. Flip and cook the other side until lightly charred and caramelized, around 3 more minutes.
8 In a bowl or dish, spread a layer of the Scallion and Chive Yogurt then start to build a tower by alternating with the crispy smashed potatoes, slices of griddle onions, and slices of smoked salmon. Finish with a drizzle of the Dill Vinaigrette, a couple more small dollops of Scallion and Chive Yogurt and garnish with a sprig of fresh dill. Best enjoyed hot or warm.