Place a large pot of salted water over high heat to boil. Place the cashews in a small bowl and add ½ cup hot tap water. Let nuts soak for at least 10 minutes. Peel and slice just four cloves of garlic and leave remaining garlic clove whole. Destem the kale and thinly slice the leaves.
Add the rigatoni pasta to the boiling water. Cook until al dente, stirring occasionally, about 5 to 6 minutes. When the pasta is done, reserve ½ cup of the pasta water, then drain the pasta. Return rigatoni to the pot, off of the heat, and toss with 1 tsp olive oil to prevent sticking.
Halve the lemon and cut half into wedges. Add the cashews and their soaking water to a blender along with roasted red peppers, red miso paste, just 1 whole garlic clove, juice from just half the lemon, ½ tsp salt, and a pinch of pepper. Blend red pepper sauce on high until smooth.
Add 2 tbsp olive oil and the sliced garlic to a large skillet over medium heat. Cook until crispy, about 3 to 5 minutes. Use a slotted spoon to transfer only the garlic chips to a bowl. Return the skillet with the garlic oil to medium heat, add the sliced kale, and cook until greens are just wilted, 2 minutes more.
Add the cooked rigatoni, a splash of the reserved pasta water, red pepper sauce, and green peas to the large skillet with kale. Sprinkle with salt and bring sauce to a simmer. Cook, gently tossing pasta occasionally, until heated through, about 2 to 4 minutes. If you prefer a thinner sauce, add more reserved pasta water by the tablespoon.
Divide red pepper rigatoni between plates and top with garlic chips. Serve with lemon wedges.