Bring a large pot of water to a boil. Once boiling, generously salt the water. Add the pasta and cook to al dente according to package directions. Reserve 1 cup starchy pasta water before straining the pasta. Set aside.
Add avocado oil to a large nonstick skillet. Season the scallops generously with kosher salt. If desired, season with cracked black pepper. Once oil is hot, sear the the scallops. Working in batches to avoid overcrowding the pan, carefully transfer the scallops to the skillet. Cook, giving the pan a gentle shake every so often, for 2-3 minutes, until a deep golden crust has formed on bottom of the scallops. Flip and cook for 1-2 minutes more, until opaque & cooked through. Transfer to a paper towel-lined plate and set aside.
Transfer the pasta back into the pot used to boil it. Add the pesto & toss to combine. While tossing, slowly add in the reserved starchy pasta water until the desired consistency is reached.
Transfer the pesto pasta to serving dish. Top with scallops, roasted red peppers/cherry tomatoes, & toasted pine nuts, lemon zest, crushed red pepper flake, thinly sliced fresh basil, grated parmesan, etc., as desired. Enjoy!