In a small saucepan, combine the rolled oats, water, and sea salt over medium heat.
Simmer for 3-4 minutes, stirring occasionally, until the oats begin to soften and absorb most of the liquid.
Lower the heat to low and slowly pour in the egg whites while whisking vigorously to incorporate them into the oats without scrambling.
Continue to cook for 2 minutes, stirring constantly, until the mixture becomes thick, voluminous, and creamy.
While the oats cook, lightly toast the chopped walnuts in a separate dry skillet over medium heat for 2 minutes until fragrant.
Transfer the oatmeal to a bowl and top with thinly sliced banana, toasted walnuts, and hemp hearts.
Finish with a dusting of ground cinnamon and serve immediately.