Slice and segment the blood oranges, saving any juice that escapes, and set aside. Wash and drain the kale. Tear it into bite-sized pieces, or slice into thin ribbons. Sprinkle with half the salt and a drizzle of olive oil, and gently rub the salt into the kale with your bare hands to break it down just a bit and release the brilliant green color. Taste, and add more salt if desired. Combine the kale with the orange segments/juice and the chopped nuts. Whisk together the olive oil, citrus zest and juice, minced garlic, black pepper and stevia, if desired. Dress the salad and toss well.