Peel shallot and garlic cloves, then finely chop. Remove stems from parsley and cilantro; finely chop the leaves. Transfer all to a bowl with a lid. Mix in oregano, vinegar, olive oil, and 1/2 teaspoon salt. Wait 15 minutes, then test flavor balance. If sauce tastes bland, sprinkle in some more salt and/or add a few more dashes of vinegar. Cover and marinate in refrigerator for 1 to 2 hours.
In a skillet, heat 1 tablespoon coconut oil over medium heat. Sauté chopped yellow onion and 2 minced garlic cloves until soft. Add chili powder, cumin, and turmeric; stir, cooking 1 minute. Pour in 1/4 cup water, stir, then mix in black beans. Heat until bubbling, then reduce to a simmer to keep warm.
Peel plantains by running a knife down the middle and peeling back the skin. Cut plantains into half-inch slices on a sharp diagonal. Heat 4 tablespoons coconut oil in a large cast-iron skillet over medium heat until the tip of a plantain slice dipped in the oil sizzles. Working in batches, place slices in a single layer with space between them and cook 2 to 3 minutes on each side until they are a deep golden brown. If the plantains are browning too quickly or start to burn, turn down the heat so they can continue to cook on the inside. If the oil isn’t sizzling and the plantains are taking too long to brown, turn up the heat so they don’t absorb the oil and become soggy. Flip with a heat-proof spatula or tongs. Transfer plantains to a plate until all of them are finished cooking.
Spoon heated rice, black beans, and plantains into shallow bowls. Top with radishes, avocado, cilantro sprigs, and lime wedges. Drizzle with chimichurri sauce.
Per serving: 1,258 calories, 36 grams fat (8 grams saturated fat), 197 grams total carbohydrates, 35 grams fiber, 46 grams protein.