Preheat oven to 400°F. On a parchment-lined baking sheet, drizzle 2 tablespoon olive oil onto the insides of all 4 spaghetti squash halves and rub it in. Sprinkle with salt and pepper and turn them over so insides are facing down.
Roast until the flesh is easily pierced through with a fork, about 40 to 60 minutes depending on size.
In a mixing bowl, combine the cabbage, beans, bell pepper, green onion, cilantro, lime juice, and 1 teaspoon olive oil. Set side to marinate.
Use a fork to separate and fluff up the flesh of the spaghetti squash.
To make avocado tomatillo sauce, combine avocado, tomatillo sauce, lime juice and cilantro and mix well.
Using the spaghetti squash as a bowl, divide the cabbage mixture into each of the halves. Top each "bowl" with 2 Tbsp of avocado tomatillo sauce and desired toppings.