Cook linguine according to package directions,in a large pot of lightly salted boiling water, stirring occasionally. After 7 minutes, add asparagus and zucchini. Continue cooking, stirring occasionally, until pasta is al dente and vegetables are tender, 5 to 7 minutes more. Drain well, and return to pot.
Meanwhile, put cashews, onion powder and salt in blender, and grind fine. Add soymilk, and blend until smooth and creamy. Set aside.
Add cashew mix, tomatoes, scallions, basil, parsley, salt and pepper to the pasta mixture. Sprinkle with cheese, to taste. Toss gently to combine, and heat over low heat, stirring frequently, 3 to 4 minutes, or until hot.