For Marmalade: Peel tangerines and reserve. Cut tangerines into supremes and set aside. Squeeze tangerine juice into a bowl and set aside. Combine the tangerine peel with enough cold water to cover in a small saucepan and place over medium-high heat. Bring to a rolling boil. Strain and repeat process 4 more times. During the fourth rinse, add water and sugar and bring to a boil. Reduce heat and leave simmering until tender and translucent, about 10 to 12 minutes. Strain and transfer orange peel to blender and reserve syrup. Puree orange peel. Thin out using reserved syrup, tangerine juice and lime juice.
To Assemble: Wrap cucumber ribbons into cylinders. Place thinly sliced snapper into tangerine and lime juice. Place snapper overlapping each other across long plate. Drizzle 1 teaspoon of juice with the minced vegetable mixture across snapper. Dot tangerine marmalade around snapper and drizzle a couple of drops of olive oil. Place cylinders around fish. Sprinkle with sea salt.
Garnish with cilantro leaves, jalapeno rounds, sea salt, and purslane. Optional, sprinkle with Tajin seasoning (powdered Mexican dried pepper condiment)