As Samraong isn't big at all you will easily find the central market with several food stalls around offering saucepans of pre-cooked food for around 2,000-3,000 Riel a serve. Unless the pots are still hot, it's a good idea to have them hear your servings up again so that you don't get more than you bargained for like getting sick. If you would like to go more for some sophisticated food, check the Santepheap restaurant (one of the best in town), where you might find some proper dishes, but don't expect Western food.
The best restaurant in town is only open for breakfast and lunch. A friendly English- and French speaking Cambodian gentleman and his family run it. They can make up most Thai Khmer dishes that you may wasn't and also serve a good breakfast of eggs, French bread and coffee. The restaurant scene in Anlong Veng is similarly limited as in Samraong. There are several local food stalls around the central roundabout offering some local dishes at very reasonable prices mostly its typical Khmer and Chinese noodle dishes.