In a bowl, combine the shrimp, lime zest, lime juice, tangerine zest, tangerine juice, orange zest, orange juice, grapefruit zest, grapefruit juice, and season with 1/2 teaspoon salt and ¼ teaspoon pepper. Stir to combine, cover and let marinade at room temperature for 30 minutes or until the shrimp are firm and opaque.
Add the tomatoes, jalapeños and cilantro. Toss to combine, taste for seasoning and adjust with salt and pepper as desired. Cover and refrigerate for 15 minutes or until chilled to desired temperature.
Trim the ends of the plantains and use your knife to score along each of the ridges. Carefully peel the plantains and cut them in half, widthwise, then use a Japanese mandoline to carefully slice them into long, thin strips approximately 1/8” thick.
Add the avocado oil to a 10” skillet and heat over medium-high until the oil reaches 350F. Working in batches, fry the plantains, flipping often, until golden brown and crispy, around 4 minutes per batch. Transfer the plantains to a plate lined with paper towel and season with a pinch of salt.
When ready to serve, stir through the avocado to the ceviche and toss to combine. Transfer the ceviche to a serving bowl and serve alongside the plantain chips.