Heat oil in a large saucepan over medium heat. Stir in red onion, salt and pepper, and cook about 5 minutes, until onion is tender. Stir in zucchini, and cook 3 to 5 minutes. Mix in garlic and tomatoes. Continue cooking, stirring occasionally, until the mixture comes to a boil.
Stir corn and cream into the mixture. Reduce heat to low, and continue cooking, stirring occasionally until thick and bubbly, 15 to 20 minutes.