In a 1 1/2- to 2-quart pan, combine rice and broth. Bring to a boil over high heat, then reduce heat to very low, cover pan, and cook until liquid is absorbed and rice is just tender to bite, about 20 minutes.
Meanwhile, in a wide bowl, mix rice vinegar with sugar. When rice is cooked, spoon it at once into bowl; mix with a fork. Let stand until lukewarm or cooler, about 30 minutes. Sliver 1/3 cup pickled ginger and add, along with bell pepper, to rice mixture. Stir with a fork to loosen rice grains and mix.
As rice mixture cools, with a sharp knife, cut peel and outer membrane from grapefruit, then cut between segments and inner membranes to release fruit; drop into a bowl. Discard peel and membranes. Sort through crab and remove and discard any bits of shell.
Mound rice mixture equally on dinner plates; top with crab and grapefruit segments. Spoon juice from grapefruit segments and the Sesame Cream Dressing evenly over salads; garnish with daikon sprouts and pickled ginger slices.