The Thai waterfall beef salad made with grilled beef and toasted rice powder is Nam Tok.
Nam tok is an Isan and Lao-style meat salad whose name means “waterfall” in Thai. The beef version is made with grilled steak, sliced thinly, and dressed with lime juice, fish sauce, dried chili, shallots, mint, and toasted rice powder. The rice powder adds a nutty aroma and slight crunch while helping distinguish the dish from other Thai salads.
A more specific Thai name for the beef preparation is nuea yang nam tok, meaning “waterfall grilled beef.” In English, however, it is widely called nam tok, making the stored answer fair for this question. It is commonly served with sticky rice and raw vegetables such as cabbage or yardlong beans.
Nam tok can also refer to a pork salad, mu nam tok, and to a separate Central Thai noodle soup darkened with blood. Those uses explain why the beef-specific wording matters. Som tum is a green papaya salad, while larb neua is a related minced-beef salad rather than the grilled-beef preparation described here.