Preheat the oven to 400 degrees and line a baking sheet with parchment paper.
In a large bowl, mix the coconut oil, lime zest, lime juice, tequila and chili powder. Add the plantain slices and toss gently to coat.
Spread in a single layer on the prepared baking sheet. Roast until plantains are lightly golden on bottom, about 15 minutes. Turn slices over, and continue roasting until evenly cooked and soft, about 15 minutes more. Depending on your oven, they might need a little longer to cook through.
If they need to be a bit more caramelized, increase oven temperature to broil, and broil until deeply golden, 1 to 2 minutes. Watch them carefully so they don't burn.
Sprinkle with flaked sea salt and serve immediately.