The popcorn crabs ($6.50) at Sushi Raku (3201 Louisiana, 713-526-8885) are so small you might almost feel guilty about eating them. Almost. An order comes with eight to ten quarter-size crabs covered in a light tempura batter and then flash-fried. They’re served with lime and a seven-spice powder known as shichimi that’s made with white and black sesame seeds, red pepper and chile powder, among other spices. Just like with soft-shelled crabs, you eat each crab whole, and the art is in picking it up with chopsticks and gently dipping it into the shichimi without getting too much spice, or the heat will overpower the flavor of the crab.