Cut off the pumpkin top and clean out all seeds and stringy pulp. Use a black marking pen to draw a jack-o-lantern face on the pumpkin. Saute onions in olive oil in a large skillet. Add meat and brown. Drain off grease. Add coconut aminos, coconut sugar, mushrooms, water chestnuts and coconut milk. Simmer, stirring occasionally, for 8-10 minutes. Add cooked rice and simmer an additional 5 minutes. Pour mixture into pumpkin. Replace pumpkin top. Place the filled pumpkin on a baking sheet and bake in a 350* oven for 1 hour. The pumpkin should be tender when removed from the oven. Place on a serving platter. Serve the pumpkin as the vegetable along with the delicious meat mixture.