Spray a wok or large skillet with nonstick spray. Preheat over medium heat. Add leeks, oregano, and garlic; stir-fry for 2 to 3 minutes or until leeks are tender. Remove from wok or skillet; set aside.
Add 1 tablespoon olive oil or cooking oil and the toasted sesame oil to wok. Add broccoli and squash; stir-fry for 3 to 4 minutes or until vegetables are crisp-tender, adding remaining oil if necessary. Return leek mixture to wok; heat through. Serve with lemon wedges. Garnish with additional basil, if desired. Makes 4 servings.