Combine oil, lemon juice, sugar, salt, pepper, parsley and mint. Mix until well blended. If made ahead, cover and refrigerate until next day.
About 1 hour before serving, cut melon in half; scoop out seeds. Cut melon into thin wedges and remove rind.
In a salad bowl, combine melon, cucumber and tomatoes. Stir dressing again; pour over salad and mix gently until well coated. Cover and let stand at room temperature for about 45 minutes, stirring once or twice.
From _Sunset Fresh Ways with Salads_ by the editors of Sunset Books and Sunset Magazine. Menlo Park, CA: Lane Publishing Company, 1987. Pg. 75. ISBN 0-376-02608-1. Electronic format by Cathy Harned.