Heat the olive oil in a skillet over medium heat. Add bell peppers and saute for 5 minutes. Add sliced corns and saute for 10 minutes, stirring occasionally. Add water and parsley pesto sauce; cook for 10 minutes or until tender. If it is too thick, add more water. Season with salt and pepper.
Meanwhile, place the spaghettini in a large pot of boiling salted water. Add some olive oil to the water to keep your pasta from sticking, and cook until al dente (or following directions on pasta package). When pasta is ready, drain and then return to the same pot; add the pesto mixture. Toss over medium heat until mixture coats pasta.
Transfer to a serving dish, sprinkle with parmesan cheese and serve. Serve immediately.