Cook pasta in boiling salted water according to directions, (usually about 10 minutes) but do not overcook. Mushy pasta will not work well for this recipe. Add a dash of olive oil to keep pasta from sticking while cooking.
In a bamboo or other type of steamer, steam the julienned carrot, fresh peas and green beans for about 5 minutes until just tender. Alternately, you could parboil them for just a few minutes to get them softened just a bit.
Drain and rinse pasta under cold water in a colander. Add to large bowl.
Mix steamed carrots, green beans and peas together into pasta. Add red bell pepper, green onions/scallions, and chopped tomatoes.
Mix ingredients for dressing together, and pour over pasta and veggies. Mix well to combine.
Place lid or plastic wrap over the bowl and let chill in refrigerator for at least an hour to let flavors meld.