These are pig ears, simmered and sliced thinly, in fish sauce and lime. There's a bit of Thai basil, some cilantro, and shredded cabbage in there too.
Usually at Thai places you'll see larb, a ground meat salad of sorts, with ground pork or beef, though larb can be comprised of any number of animal parts. I got the idea for this dish from Zabb Elee, an Isan Thai restaurant here in New York. The exact dish on the menu was "ground pork, pig ear and liver larb," and darn if I didn't fight my friend for the slices of tender pork liver and the slivers of gelatinous ears.
I really enjoy the larb with pig's ears. The pig skin soaks up the marinade, and then you get the crunch of the cartilage with every bite. Since I'm usually deep-frying my pig's ears as a topping for salad, it's nice to use the ears as the main ingredient in the salad itself.
Still the dish could just as well become tripe larb, or trotter larb, or any combination thereof using ears, liver, tripe and more. And if you think about the range of livers (chicken, duck, pork, or beef) you can use to make larb, the options are manifold.
Actually I think any animal parts tossed in fish sauce and lime, with fresh herbs and vegetables, will be something you will want to eat again and again. Whenever I make some animal part, I set aside a little to larb-ify. I have not been met with a part yet I didn't like larbified.