Soak the rice noodles in boiling water for about 5 minutes, or until soft and rinse.
Let drain fully in a strainer in the sink.
Cut the bok choi in half and drizzle with sesame oil.
Heat the grill pan over a high heat and coat the tuna with toasted sesame oil and season with salt and pepper.
Place the tuna and the bok choi into the pan and grill for about 3 minutes per side. A little longer if you’d like your tuna more well done.
To make the sauce whisk all the ingredients together.
Place the noodles in a bowl and toss with a drizzle of sesame oil and a light sprinkle of sea salt.
Slice the tuna into strips and lay over the noodles with the bok choi on the side.
Drizzle the sauce on top and sprinkle the the cilantro and sesame seeds.
Serve with lime wedges and avocado slices.