Place the cooked beets, chickpeas, tahini in a blender bowl, sprinkle with lemon juice and olive oil, salt and pepper to taste. Mix in a blender until smooth and thick sour cream-like.
Mix apples with herring and season with mayonnaise.
Toast the baguette slices in the oven until crispy.
Place beetroot hummus on a slice of baguette, top with herring and apple mixture.