Cook the pasta for 8 minutes in plenty of boiling salted water. Drain on a sieve. Rinse the corn. Clean the peppers and cut into small cubes. Cook the frozen peas in boiling salted water for 5 minutes and then drain.
Put the cooled noodles and all other salad ingredients in a bowl and mix well.
Mix the onion with the vinegar, salt, pepper and sugar, then slowly stir in the oil. Put the marinade under the salad and mix everything well.