Slice the salmon: Slice your salmon into strips roughly 1/4 thick or even a little thinner. You ultimately want to cut enough pieces so you will have just enough to cover all of your rolls when draped over the top. Many pre-packaged smoked salmon will already come sliced. Cut the nori sheet in half: Fold the nori sheet in half. Carefully tear the nori sheet in half along the crease. If it doesn't tear easily, use kitchen shears to cut the nori sheet in half.
Cut the avocado and cucumber: Slice the avocado in half the long way. Remove the seed and cut each half into 8 slices. Each whole avocado should yield around 16 slices. I would also drizzle a little lemon juice over your cut avocado to prevent it from browning in your roll. You will then need to cut the cucumbers into strips that are as long as your nori sheet and about 1/8 inch thick. Prepare your bamboo sushi mat: Cover your bamboo sushi mat with plastic wrap. This will help keep the rice from sticking to it.
Press rice onto nori sheets: Next, place the nori sheet onto the plastic wrap with the shiny side facing down. Then press around 1/2 cup of rice onto the nori sheet in an even layer. Tip: Wet your hands in a bowl of water and a splash of rice vinegar prior to handling the sushi rice. This will prevent the rice from sticking to your hands.
Flip nori sheet over: Gently flip the nori sheet over so the rice is facing down. You will add the filling directly to the nori sheet with the rice on the outside.
Add the crab: Spoon about 1/4 of the crab salad mixture onto the nori sheet and spread evenly across the middle of the sheet.
Add the avocado and cucumber: Add the avocado slices and cucumber sticks horizontally along the nori sheet. In general, I add 2-3 avocado slices and 1-2 cucumber sticks depending on the size of each ingredient and how everything fits.
Roll the sushi: Use the bamboo sushi mat to fold your roll until it is completely enclosed. Once the rice is making contact with the nori sheet, pull back the sushi mat so it doesn't get caught in the roll. Still using the sushi mat as your guide, finish rolling until the roll is completely wrapped. Then wrap the sushi mat around the roll and gently press, tightening the roll together.Keep in mind that rolling sushi is an art that may take some practice so don’t get frustrated if it doesn’t look perfect your first time. It will get easier the more you do it. Drape your salmon over the roll: Cover each roll by draping a piece of salmon over the top slightly overlapping each other. Once the roll is covered, use your sushi mat (still covered in plastic wrap) to wrap the roll and press the salmon onto the roll so it will cut as one roll.
Cut the roll: Using a sharp knife, cut the roll into 8 pieces. I do this by first cutting the roll in half. Then cutting each half in half. Then cutting each fourth in half. Tip: Be sure to clean and wet the edge of your knife before cutting each roll.
Serve and enjoy: I usually serve with soy sauce and wasabi. Sushi rolls are traditionally served with pickled ginger as well.