Bring a large pot of water to a boil and salt it.
Heat a skillet, grill pan or outdoor grill to medium-high. In a large bowl, drizzle the scallions with canola oil if grilling, or add canola oil to the grill pan, 1 turn of the pan. Season the scallions with sea salt and pepper, then sear or char until lightly caramelized at the edges and blackened in a few spots, about 3 minutes. Place in a food processor and let cool.
Drop the pasta into the boiling water and cook until al dente.
Add the garlic, herbs, parmigiano-reggiano, lemon zest and EVOO to the scallions; pulse into a thick pesto. Transfer to a serving bowl. Season with salt and pepper.
Just before draining the pasta, add about 1 cup of the pasta cooking water to the sauce and stir to combine. Drain the pasta; toss with sauce 1 to 2 minutes. Top with ricotta salata and serve.