I recently taught a gluten free cooking class at ICE (Institute of Culinary Education) and used rice flour to get a beautiful golden crust on salmon. Other mild-flavored flours that also work well include: specialty gluten-free flour mixes (which can be more costly and often are used for baking), corn flour (which is finer than cornmeal), and potato starch flour.
To learn more about gluten-free cooking, see our collection of gluten-free recipes and check out the new cookbook from Oxmoor House, The Cooking LightGluten-Free Cookbook. (It's the one with pizza on the cover!).