Tip the sesame seeds onto a plate and set them aside.
Mix together the mirin, soy sauce, honey and sesame oil in a bowl then pour half into a small ramekin. Add the rice wine vinegar to the ramekin and a couple of sliced spring onions then stir and set aside.
Pour the remaining sauce over the tuna steaks and ensure all sides are coated.
Heat a pan over high heat and add a tablespoon of olive oil.
Coat the tuna steaks in the sesame seeds pressing them into the fish then place the steaks into the hot pan.
Cook for a minute or two on each side.
In the meantime, heat a little olive oil in a separate frying pan on high and add in the sugar snap peas and sliced spring onions and saute for a few minutes until cooked but still crunchy. Add a splash of red wine vinegar towards the end of cooking.
To serve, tip the peas and onions into a serving bowl, slice the tuna and spread onto a platter and place the ramekin of dipping sauce alongside.
Sprinkle any remaining spring onions over the top of the tuna.