Whole-wheat pasta would be a tasty option here, complementing the earthy flavor of kale. Beyond tenderizing the kale, a quick blanch helps preserve its deep-green color in the pesto, even as it coats hot pasta. Pecorino cheese is a little more pungent than Parmigiano-Reggiano, so it stands up nicely to the kale. We love the bright floral note the lemon rind adds to the pesto.
Bring a large pot of water to a boil. Fill a large bowl with ice water. Working in two or three batches, submerge kale in boiling water for 15 seconds until wilted and deep green; remove, and immediately plunge into ice water for 15 seconds. Drain kale well; place on layers of paper towels, and press to remove excess liquid. Place kale, pine nuts, and garlic in a food processor or blender. Pulse until coarsely chopped. Slowly add oil with motor running; blend until pesto is smooth. Place pesto in a medium bowl; stir in rind, cheese, salt, and peppers.
Cook pasta according to package instructions, omitting salt and fat. When pasta is al dente, drain, reserving 1 cup pasta cooking liquid. Return pasta to pan over medium-low heat; stir in pesto. Add pasta cooking liquid, 1 tablespoon at a time, until sauce reaches desired consistency.