Bring a large pot of salted water to a boil. Add the pasta. About 3 minutes before the pasta is due to finish cooking to al dente (according to package instructions), add the asparagus and cook an additional 3 minutes, or until the pasta is al dente. Reserve 1 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 20 to 30 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 2 to 3 minutes, until soft. Add the arugula and peas and cook another 2 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.
TO STORE: Refrigerate pasta in an airtight storage container for up to 4 days.
TO REHEAT: Rewarm leftovers in a Dutch oven on the stovetop over medium-low heat or in the microwave.
TO FREEZE: Freeze pasta in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.