Tuna Tartare for the Keto and Low Carbers

0 Place garlic, sesame oil, soy sauce, serrano pepper, green onion, juice of lime in a bowl.  Set aside. 
1 Start chopping tuna up into small cubes.   I initially cut 1 inch cubes then halved those to smaller 1/2 " cubes.  When finished, place tuna in bowl with marinade and sprinkle with salt and pepper to taste and mix well.  Set aside.
2 Cut avocado into small bite size pieces, small cubes similar in size to tuna.   
3 Place a biscuit cutter in center of a plate, and start stacking avocado in center and pushing down with back of a spoon.    Then add the tuna as your next layer, and push down with back of spoon.    Gently slide the biscuit ring off and see your lovely creation. (If you do not have a biscuit cutter, you can use a large rimmed glass then invert when you finish stacking).
4 Optional:  I mixed together a  tablespoon of mayonnaise and 1 tablespoon of Sriracha and added this to a small bag.  I cut the corner of the baggie and drizzled the sauce over the top of the tartare.   Sprinkle rice seasoning (Furikake) or Trader joes everything but the bagel seasoning & add a garnish of fresh micro greens.