Using a very sharp knife, trim away any skin from the tuna fillet. Cut the tuna into 1/4-inch cubes and place in a bowl. Add the chili marinade ingredients, minus the chili paste, to the blender and emulsify. Mix in the chili paste into the marinade then pour onto tuna and add salt to taste at the very end.
Use a mandolin (or a vegetable peeler) slice the cucumbers to be paper thin in the end result. When the cucumbers are sliced, roll them up and set to the side.
Slice the shallots then and then fry them. To fry the shallots: Place 1/4 cup of avocado oil or oil of choice into a small saucepan. While the oil is cold, add in the sliced shallots. Bring to frying temperature (375ºF) and fry until golden. Watch often to avoid burning. Set aside on a plate lined with paper towel until ready to serve. *The key is not heating the oil beforehand.
While the tuna is marinating, cut the watermelon into half-inch cubes (2 cups) and lightly season with salt t o the watermelon to bleed.
Assemble: Add the tuna and place a few watermelon cubes, garnish with shallots and cucumber rolls, top with cilantro and micro greens.