Place the sesame seeds in a frying pan (with no oil) on medium heat and toast for 3-5 minutes, stirring to ensure they brown evenly.
Put 2 tablespoons of the toasted sesame seeds in a pestle and mortar and grind until they are broken down into a crumbly mixture.
In a bowl combine the honey, tahini, tamari, water and ground sesame seeds and whisk together.
Remove the tops of the green beans and cut in half if they are quite long. Bring a pot of water to a boil and cook the green beans for 4 to 5 minutes until they are tender but not mushy. Remove from the heat and quickly rinse in water once they have reached the desired doneness before plunging in a bowl of ice cold water.
Once the beans have cooled, drain and place in a bowl. Top with the sauce and stir until they are well coated. Sprinkle with the remaining 1/2 tbsp before serving.