A. Buying fish to serve raw can be scary. Still, several local markets offer sushi-grade flesh that I'm comfortable feeding to my own kids. When I'm planning a small-scale, roll-your-own gathering that requires just some tuna and salmon, a couple of avocados, horseradish sprouts, cucumbers, carrots, wasabe (you can get it powdered and add water), sheets of nori for rolling and sushi rice, I simply head to any Alfalfa's, which always has sushi-quality tuna on hand, and almost always king salmon, too -- along with everything else on that list.
For variety, you can't beat the selection -- or the freshness -- at Pacific Mercantile (1925 Lawrence), which offers tuna and salmon all the time, mackerel sometimes, and usually sushi-grade squid and octopus. Cherry Crest Seafood Market & Restaurant (5909 South University Boulevard) also sells quality tuna and salmon, along with mahi-mahi and halibut.
And for the most user-friendly sushi-rice recipe, check out Seductions of Rice, by Jeffrey Alford and Naomi Duguid (Artisan, $35); the recipe is so failproof that I was able to make sushi rice on a camp stove.