In a dry skillet over medium heat, toast sliced almonds for 3–4 minutes, stirring frequently, until golden and fragrant. Watch closely so they don't burn. Set aside to cool.
In a blender, add all your ingredients and blend until smooth and creamy (30-60 seconds).
In a large bowl, combine the arugula and/or spinach, chilled lentils, feta crumbles, blueberries, cucumber, red onion, and feta.
Drizzle the chilled blueberry dressing over the salad and toss to coat. Top with toasted almonds and more feta crumbles if desired. Taste and add more salt and pepper if desired. Serve immediately or chill for 30-60 minutes.
