Add kale to a large bowl, season with ½ teaspoon salt, and massage until kale is slightly softened, about 30 seconds. Add Swiss chard and toss to combine.
Bring a large pot of water to a boil over high heat; season heavily with kosher salt (about a tablespoon). Add lentils, reduce heat to medium and simmer, uncovered, until lentils are tender yet slightly al dente; 20–25 minutes.
Meanwhile, using a vegetable peeler, peel four 3-inch strips of lemon peel, making sure to avoid white pith; reserve lemon for later. Add lemon peels to a small skillet with scallion whites, smashed garlic cloves and oil.
Heat skillet over medium and cook oil mixture, stirring occasionally, until garlic starts to brown and lemon peels start to curl and toast, about 3 minutes. Add almonds and cook, stirring frequently, until almonds are browned, 3–4 minutes. Off heat, stir in cumin seeds and red pepper flakes and let rest in oil 1–2 minutes.
Strain mixture through a fine-mesh sieve set in a small bowl; reserve oil. Pour nut mixture onto a paper towel-lined plate, making sure to get all of the cumin seeds; season with salt and let cool. Discard lemon peels.*
Once cool, mash cooked garlic cloves into a paste using the side of a Chefs knife; transfer to bowl with reserved oil. Juice reserved lemon (should measure about ¼ cup); add to oil and garlic and whisk to combine.
Using a strainer, drain lentils well; add to bowl with kale and Swiss chard.
Add reserved scallion greens, half of the almond mixture, oil mixture, feta, olives, cucumber and parsley; toss to combine. Season with salt and pepper to taste. Transfer to a serving dish and top with remaining almond mixture.