Process baby kale and cilantro in a food processor until finely chopped. Add walnuts, miso, garlic, sesame oil, juice, zest, salt, and pepper flakes; process until a finely minced and nearly resembles a paste; scrape down sides of bowl. With processor running, slowly drizzle in oil and process until smooth; season with additional salt and set aside.

Season shrimp with salt and pepper, then thread onto four skewers. Coat a grill pan or cast iron skillet with nonstick spray. Heat pan over medium-high and grill shrimp until pink and cooked through, 2–3 minutes per side.

Cook ramen noodles in a large pot of boiling salted water according to package directions. Reserve 1 cup cooking water, then drain and transfer ramen to a large bowl. Add three quarters of the pesto to the noodles and toss to combine. Add pesto to cooked noodles and toss thoroughly combine, gradually add reserved pasta water to reach desired consistency.

Divide noodles and shrimp skewers between serving dishes and sprinkle with sesame seeds.