Heat oven to 425°F. Toss zucchini and pepper with roasting oil and vegetable salt; roast on wide rimmed pan 20 to 25 minutes, stirring once, until tender with browned edges. Cool 10 minutes.
Meanwhile, boil orzo with tablespoon salt until fully tender. Drain thoroughly; spread in shallow dish 10 minutes.
Whisk dressing oil, lemon juice, zest, oregano, dressing salt, and pepper. Toss half through warm orzo.
Fold in cooled vegetables, beans, parsley, feta, and remaining dressing. Serve cool or promptly refrigerate covered.
Stir before serving; refrigerate leftovers within 2 hours.