These bowls are infinitely customizable—add fresh radishes, jalapeños, roasted sweet potatoes or butternut squash. If you expand beyond the Whole30 world, toss in corn chips, grilled corn or black beans.
Combine the cabbage and lime juice in a bowl and toss well. Season to taste with salt and pepper and toss again. Set aside while you prepare the rest of the ingredients.
Combine ⅓ cup chopped onion (reserve the remaining for cooking with the turkey) with the chopped tomatillos, kiwi, jalapeño and cilantro. Season with ½ teaspoon each salt and pepper.
Heat the olive oil in a large skillet over moderately high heat. Add the garlic and the remaining onion and cook, stirring occasionally, until softened, 6–8 minutes. Add the frozen burgers and cook, breaking up the burgers with a wooden spoon, until meat is crumbled and no longer pink, 5–8 minutes.
Add the chili powder, cumin and ½ teaspoon salt to the turkey and cook, stirring occasionally, until cooked through, about 6 minutes more. Remove from the heat.
To serve, divide the cabbage among 4 bowls and top evenly with the turkey mixture, avocado slices and salsa. Serve at once.