Yes, yes you do. Quinoa contains saponins, a natural "insecticide" that keeps bugs away from the plant. Genius in nature, unpleasant in the kitchen. Saponins are bitter and if you think you don't like quinoa I bet it's because you haven't rinsed it. Yes, this is an annoying step that takes a full 2 minutes. Do it, I promise it's worth it. Rinse in a fine-mesh sieve under cold water until the water runs clear.