Cut out and discard the tough central rib from each kale leaf. Bring a large pot of salted water to a boil over high heat. Add the kale leaves and boil until tender, about 5 minutes. Drain and rinse under cold water to stop the cooking. Squeeze dry and chop coarsely. You should have about 3/4 cup.
Put the kale, 1/2 cup of the walnuts, and the garlic in a food processor and blend until finely chopped. With the motor running, add the olive oil gradually through the feed tube and blend until smooth, scraping down the sides of the work bowl one or twice. Transfer to a bowl and stir in the cheese. Season the pesto highly with salt.
Bring a large pot of salted water to a boil over high heat. Add the pasta and cook until al dente. Just before the pasta is done, scoop out 1/2 cup of the boiling pasta water and whisk it into the pesto to thin it. Scoop out and set aside another 1 cup of the pasta water . Then drain the pasta and return it to the warm pot off the heat. Add as much of the pesto as you like; you may not need it all depending on how well sauced you like your pasta. Toss with tongs, adding as much of the reserved pasta water as needed to keep the noodles from clumping.
Divide among individual bows. Top each portion with a shower of cheesed with the remaining 1/2 cup walnuts, dividing them evenly. Pass additional cheese at the table. Serve immediately.