Directions:

1. Wash and roughly chop greens. Use the stems too, which should be finely chopped. Squeeze and shake out any extra water. Pat dry with paper towels.
2. Heat 2 tablespoons olive oil over high heat in a large, high-edged, covered skillet. Add greens and toss until well coated. Cover pan and allow to cook for 1 minute, then toss again. Reduce heat to medium, cover and cook several minutes more, tossing occasionally, until wilted. They should be soft, but not mushy. Stir in sea salt, cover, and remove from heat.
3. Line a plate with paper towels. In a large frying pan, heat remaining oil and butter together. To peel plantains, pierce the skin with a knife and run it down the fruit lengthwise. Slice into thick, diagonally-cut discs, about 3/8-inch each. Drop plantain slices into the hot pan and fry about 4 minutes per side, until very brown and caramelized. Remove to drain on paper towels.
4. To heat tortillas, sprinkle lightly with water and stack in a dry pan over medium heat. After a minute or two, flip the entire stack and then flip just the tortilla on top. Allow to heat for another minute, then flip the entire stack and then the two tortillas on top. Continue this process, working your way down the stack, until all tortillas are warmed through.
5. To assemble the tacos, spoon a generous heap of greens into a tortilla and top with 2 or 3 slices of plantain.