Most Chinese restaurants in San Francisco are Cantonese, which is not bad, but it can be worth it to search out those few restaurants that specialize in other regional specialties.
Such as Spices II, which is szechuan, known for their prolific use of chili peppers. The best items on the menu are their szechuan dishes, which are easy to distinguish with descriptions such as "numbingly hot", "firecracker", etc. My favorites are the noodles topped with spicy ground meat, the dry braised green beans (not spicy but perfectly cooked), and the huge pile of sliced beef dripping in chili oil. The latter probably isn't the healthiest option, but it was truly delicious.
I haven't tried them yet, but their hotpots look great too.