Cut watermelon into cubes and remove seeds. Place in a baking dish.
In a mixing bowl, combine liquid aminos, sesame oil, ginger, garlic, lime juice, nori, scallions, cilantro, and crushed red pepper. Mix well.
Pour the marinade over the watermelon, ensuring all pieces are coated. Cover and refrigerate for 8–10 hours to allow the watermelon to absorb the flavors.
Preheat oven to 350°F (175°C).
Bake the marinated watermelon in the oven for 20 minutes. Let cool before assembling the poke bowl.