How to Make It
Preheat oven to 450°F. Line a baking sheet with parchment paper. Toss potatoes with 3 tablespoons oil, 1 teaspoon chili powder, 1 teaspoon salt, and ￼¼ teaspoon pepper in a large bowl. Arrange skin side down in a single layer on prepared baking sheet. Roast, stirring once halfway through, until tender and crispy, 35 to 40 minutes
Meanwhile, stir together turkey, onion, and remaining 1 teaspoon chili powder and ½￼ teaspoon each salt and pepper. Divide mixture into 4 equal portions, then form into scant ￼¾-inch-thick patties.
Heat remaining 1 tablespoon oil in a large cast-iron skillet over medium-high. Add patties and cook until charred on both sides and cooked through, about 4 minutes per side.
Stir together mayonnaise, lime zest, and lime juice. Assemble burgers on toasted buns with lime mayo, avocado, and lettuce. Serve with potato wedges and any remaining lime mayo on the side.