Rinse the quinoa in a fine-mesh strainer under cold running water for about 30 seconds, then drain well.
Add quinoa and water (or nut milk) to a medium saucepan. Bring to a boil, then reduce to a gentle simmer, cover, and cook for 15 minutes.
Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork.
While the quinoa cooks, toast almonds, walnuts, pumpkin seeds, and sunflower seeds in a dry skillet over medium heat for 3–5 minutes, stirring often, until fragrant. Transfer to a plate to cool.
Prep the toppings: wash berries (or thaw frozen) and slice or mash the banana.
Assemble: divide warm quinoa among 3 bowls. Stir in vanilla and cinnamon, then pour in almond milk (start with about 1/3 cup per bowl). Top with berries, banana, toasted nuts/seeds, and goji berries if using.
Finish with maple syrup to taste and an extra dusting of cinnamon. Serve warm, or chill for a cold bowl.