Bring a large pot of salted water to a boil. Add the pasta. About three minutes before the pasta is due to finish cooking to al dente, add the asparagus and cook an additional three minutes, or until the pasta is al dente. Reserve one cup pasta water, drain the pasta, and set aside.
While the pasta cooks, prepare the sauce. Add the avocado, garlic, Greek yogurt, parsley, basil, lemon juice, salt, and pepper to a food processor or blender. Process on high for twenty to thirty seconds, until smooth, stopping to scrape down the bowl as needed.
In a large saucepan or Dutch oven, heat the olive oil over medium low. Add the green onion and cook two to three minutes, until soft. Add the arugula and peas and cook another two minutes, until the arugula is wilted. Remove the pan from the heat and stir in the drained pasta and asparagus.
Add the avocado sauce and toss gently to combine, adding a bit of the reserved pasta water as needed if the pasta is too thick or clumping together. Taste and add additional salt and/or pepper as desired. Serve immediately.
