Place the peas in a bowl, and cover with just boiled water. Let sit for 30 seconds, then drain and rinse in cold water.
Blanche the kale/spinach in boiling, salted water for 1 minute. Drain, and pat dry.
Transfer the peas, kale, garlic, nuts, parmesan cheese, and a healthy pinch of salt to a food processor. Mix until everything is chopped, and drizzle in just enough oil to keep it moving.
Add a splash of lemon juice and a sprinkle of chilli flakes, to taste. Add any more salt if desired.
Cook the pasta according to the package directions, and drain, reserving a ladle of the pasta water.
Add a splash of the pasta water into the pesto, and whizz to combine. Stir together the pasta, and pesto, adding more water to give it a silky texture. Taste, and serve with extra parmesan or chilli flakes.