In a blender, combine all the pesto ingredients except the olive oil. While blending, drizzle in the olive oil until the pesto has reached desired consistency. Taste, and add more salt or lemon juice as needed. Set aside.
Cook pasta until al-dente, if serving the salad warm, or just past al-dente, if you plan to serve it cold or at room temperature. Reserve ¼-1/2 cup pasta water before draining.
Thin the pesto with 2-3 TBSP pasta water to create a more sauce like consistency, then pour the pesto over the pasta while it is still warm. Toss to combine, adding more pasta water as needed until the pasta is coated evenly.