Thinly chop kale and coarsely chop toasted hazelnuts. Place chopped kale in a large bowl and set aside with other salad ingredients.
In a medium frying pan over medium-high heat, warm olive oil and smoked salt. After about a minute, test the oil with a droplet of water. When it sizzles, add thinly sliced leeks and reduce heat to medium. Distribute evenly and swirl in pan as the leeks begin to brown. Stir gently with a silicone spatula to bring any quicker cooking leeks to the center of the pan for an even cook. Once they turn a golden brown, remove from heat and quickly drain oil into a bowl to use for salad dressing. Set crispy leeks aside in a separate bowl.
In another bowl, whisk 2 tablespoons of olive oil from crispy leeks with red wine vinegar, sea salt, and black pepper. Let cool at least 10 minutes.
Once vinaigrette is at room temperature, pour most of it over chopped kale and gently massage, tossing to incorporate. Add crispy leeks (reserve a few tablespoons for garnish), apple slices, feta, pomegranate, and toasted hazelnuts, tossing gently. Top with the remaining tablespoons of crispy leeks and a few extra pomegranate arils. Serve immediately.