Bring a large pot of generously salted water to a boil. Add the pasta and cook until al dente, according to package instructions. Strain, rinse thoroughly with cold water to cool, shake off excess water, and transfer to a large serving bowl.
Meanwhile, add the artichoke hearts to a food processor***. Pulse about 10 times, or until they're chopped and take on a flaky texture. Carefully gather the chopped artichokes within a piece of cheesecloth or a nut milk bag (or your hands if these aren't an option), and press as much excess water from them as possible. Releasing the excess liquid ensures a more "tuna-like" texture. Add to the serving bowl.
Next, prepare the peas, celery, and onion. Add to the serving bowl with the flaked artichokes.
In a medium bowl, whisk together the mayonnaise, lemon juice, salt, and pepper until smooth.
Pour the dressing over the salad and toss to coat. Taste and season with more salt and pepper to taste. If you like a creamier salad, add a bit more mayo as well (2–4 tablespoons).
Refrigerate until ready to serve.
Leftovers will keep for up to 5 days in the refrigerator.