Prepare guacamole by combining all the ingredients in a bowl. Place 1/4 of guacamole mixture into bottom of a ring mold set on a plate, making sure it is pressed down and evenly distributed.
To make the orange sauce mix all the ingredients together until well combined.
Dice tuna. Season with salt and pepper and mix with the sesame seeds, scallions and 2 tablespoons of the orange sauce. Add additional salt and pepper to taste.
Layer 1/4 of the tuna mixture on top of guacamole in ring mold, gently pressing down to evenly distribute.
Mix together mayonnaise, Sriracha and lime juice. Dress the plate with 3 small drops of Sriracha sauce brushed by a spoon. Top tartare with potato crisps.
Remove ring mold. Repeat to yield four servings.