Toast walnuts in a small skillet over medium-low heat, tossing often, until oils start to exude and nuts look shiny, about 5 minutes. Increase heat to medium and stir in date syrup and butter. Cook 2 to 3 minutes, stirring often, until mixture thoroughly coats nuts. Transfer nuts to a piece of parchment paper and allow to cool while you prepare pancakes.
Combine bananas, yogurt, tahini, egg, and almond milk in a medium bowl; mix well. In a separate bowl, combine flour, cinnamon, baking powder, and salt; stir with a whisk. Pour flour mixture into banana mixture; stir until combined.
Heat coconut oil or butter in a griddle or large skillet over medium heat. Working in batches, scoop 1/4-cupfuls of batter onto griddle. Cook pancakes until bottoms are golden brown and bubbles form on top, about 3 minutes. Flip and cook until other side of pancakes are golden brown, about 2 minutes longer. Serve pancakes with candied walnuts and additional date syrup, if desired.