Bring a large saucepan of salted water to a boil. Add the snow peas and cook until crisp-tender and bright green, about 2 minutes. Drain the snow peas and spread them on a cookie sheet to cool to room temperature. Slice the snow peas lengthwise 1/4 inch thick.
Heat the oil in the saucepan. Add the tomatoes and cook over moderately high heat until they release their juices, about 2 minutes. Add the snow peas and cook, stirring, until heated through, about 1 minute. Season with salt and pepper and serve.