If you are vegan or vegetarian, you might want to emphasize no fish,shrimp,flakes,etc. I worked in a Chinese restaurant for a few years and TBH, a lot of Asian cultures do not have a concept of fish not being vegetarian or vegan. It just doesn't compute
It's a cultural thing
But to answer the question, my favourites:
Szechaun Spicy Green Beans (order with no minced beef)
Ma Po Tofu (again, emphasize no minced beef, it sometimes comes with it)
Special order: Singapore Noodles, order without the shrimp or chicken. Spicy, curry