Optional - Rinse sesame seeds well in lots of water and soak them for at least 2 hours. Later drain the water and rinse them well. Also soak cashews for 2 hours or longer. Pour half cup water and blend them until very smooth.
Peel the oranges and remove the pith. Separate each orange to 2 parts. Cut open each part such that, all the segments open up in the center. (check picture in the post) Seeds are easily visible. Remove them.
Add all the ingredients - yogurt, chopped bananas and orange segments to the blender. If using tahini and cashew butter add them too.
Blend until smooth with a splash of water or orange juice. For a thinner orange banana smoothie add more water or juice.
Pour orange banana smoothie to serving glasses.