Using a vegetable peeler, peel "ribbons" of the zucchini, squash, and carrots; that is, run the peeler along the vegetables lengthwise to make long, thin strips. Use as much of the vegetables as possible, leaving the core and seeds behind.
Heat vegetable oil and sesame oil in a large pan.
Add carrots and saute for a minute or two.
Add zucchini and squash and continue to saute until they start to soften.
Add soy sauce and continue to saute until veggies are desired tenderness.