Take your time. Ordering at the counter is daunting for hungry first-timers. Don’s menu offers 10 different types of sandwiches, most under $3, as well as over 30 other items. Choices include traditional dishes such as pho, rice vermicelli with grilled meats, and spicy green papaya salad. Their barbecue beef, chicken, and pork sandwiches are the most popular with the uninitiated. But if you want to eat like the cognoscenti who grew up eating Vietnamese sandwiches, get the “special” with cha lua (Vietnamese bologna), Chinese-style barbecue pork, pâté, and a slice of gleaming offal-and-gelatin headcheese.