Cook the soba noodles according to packet directions. Mine took 4 minutes to boil. Make sure you don't overcook them.
While the noodles are cooking, mix the satay sauce ingredients together in a small dish. If your nut butter is thick it might take a bit of mixing, but it will combine to become a smooth sauce in the end.
Once cooked, drain the noodles in a sieve and run under cold water to cool them down. Let them drain for a few minutes (you don't want soggy noodles!).
Put the noodles in a bowl and pour over about half of the sauce. Use your hands to toss it through the noodles, ensuring they're evenly coated. You really do need to use your hands because a spoon or other utensil would crush and break the noodles.
Assemble a sushi rolling mat with a sheet of nori on top, rough side up. Spread half of the noodle mixture evenly over the nori, leaving a gap of 2-3cm across the back edge. Line up avocado slices or other filling across the front edge.
Use your finger and some water to wet the back edge, then use the sushi rolling mat to help roll the sushi. Try to get the rolls as firm as you can, but remember this isn't rice and they won't be as firm as a typical sushi roll.
Repeat with the second nori sheet.
If you're eating straight away, use a sharp knife to slice each roll into pieces. If you're making these to eat later, or tomorrow, put the rolls in the fridge (covered) to chill until you need them. Chilling will help them firm up a bit more too.
Serve with the remaining satay sauce, for dipping.