In a medium bowl, combine the coconut aminos, sambal oelek, ginger, rice vinegar, sesame oil and sesame seeds and whisk until well incorporated. Add the cubed tuna to the bowl and stir gently to coat the fish. Refrigerate for 10 to 15 minutes.
Meanwhile, make the spicy mayo: simply combine all the ingredients and mix until well incorporated.
To serve, place about 1 cup of rice at the bottom of each bowl, top with your choice of vegetables and then spoon the fish over the veggies, dividing it equally between all four bowls. Save the leftover marinade to drizzle over the bowls, along with the spicy mayo.