Freeze banana slices for at least 30 minutes or up to 1 day.
Place banana, spinach, pineapple, coconut water, kiwis, hempseed, salt, and, if desired, ginger and honey in a blender; process until smooth, 20 to 30 seconds, stopping to stir and scrape down sides as needed. (If mixture is too thick, add up to 4 tablespoons coconut water and process again.) Divide between 2 bowls and sprinkle with toppings. Serve immediately.