Churros are crispy on the outside, chewy on the inside. They are also usually sprinkled with sugar and cinnamon. Chinese donuts are fluffy soft, not crispy, and also use a much different dough and don't have cinnamon. They are also fat and round like you would expect of something called donuts, whereas churros are sticks with a star shape.
I swear in all my years I've never seen them even once. My cousin's Chinese restaurant did not serve these. None of my family or friends have ever ordered it. Please tell me the name of one place in the Sunset that has these and I will make it a point to go out and try one these puffy curiosities, authentic or not. And after that I'll probably go get some San Tung wings.
Win Fook on Noriega and 45 has sweet and sour chicken. But the way they do it is different. They mix the sauce in with the chicken instead of having you dip it. So it won't be exactly like the kind in the OP but very similar. Ask for the sweet and sour chicken rice plate for $5. I lived three houses down from that restaurant. I miss SF so much.
San Tung had the best fucking chicken wings I've ever eaten in my life. Fantastic.