Roulade
Skin the salmon fillet and remove the blood line. Trim the tail off so and split the fish from top to bottom. This will leave you with a thick loin being one piece and the thinner belly being the other. Take the thicker loin and butterfly it length ways. Season it and roll in plastic wrap to form a long cylinder, tie the ends to hold the shape and steam for 8 minutes. Allow to cool and rest, 24 hours is best.

Tartare
Dice the tuna into 1/8 10mm dice. Place in a bowl add salt, pepper, herbs, ginger, olive oil, diced cucumber, ginger and half the lime juice. Check the seasoning and adjusts necessary.

Potato Trellis
Peel and thinly slice the potatoes. Cut them into strips 2 inches by 1/4 of an inch. Lay the strips on a 'sil pat' three down by three across. Place another 'sil pat' on top and bake at 350 F for approximately five minutes, or until golden brown.

Sauce
Season the sour cream add the chives and thin with a little water to pouring consistency.

To Finish
Slice the roulade (1/2 inch thick or so). Place in a two inch ring, season. Fill the remainder of the ring until the tower is about three inches high. Finish with a layer of caviar. Place on a plate and remove the ring take the long sliced cucumber and cut the flesh in to a long ribbon about five inches long 12cm. Wrap this around the middle of the stack to hide where the tuna and salmon join. Spot some sauce around and finish with the potato trellis and long cut chive...