The spicy roast crab at Vietnamese resto Yummy Yummy is hands down the best of its kind in SF.
The uber garlicky-fiery chile sauce is out of this world. My folks, whom I took there while they were in town, gave it the highest of all compliments (in their book), saying this had exactly the flavor components of an excellent Korean marinade (mind you, I did say Yummy Yummy is in fact a Vietnamese establishment).
My ma, who doesn't really care for crab at all, couldn't help but sneak a leg or 2 or 3 onto her plate; it was the garlic-chile-onion-scallion-sesame sauce that she was in love with. And so was I—oh yes, and the crustacean itself was damn good too.