1. Light the grill. In a shallow dish, combine 3 tablespoons of the oil with two-thirds of the minced garlic. Coat the chicken with half of the garlic oil and season with 1/4 teaspoon of the salt and 1/8 teaspoon pepper. Grill the chicken over moderately high heat, basting with the remaining garlic oil, until just done, about 10 minutes per side for the breasts, 13 for the legs.
2. Meanwhile, in a medium saucepan, heat the remaining 1 tablespoon oil over moderately low heat. Add the onion and cook, stirring occasionally, until translucent, about 5 minutes. Add the remaining garlic, the ginger, and the jalapeños, and cook, stirring, for 1 minute longer. Add the tomatoes, the coconut milk, the remaining 1/2 teaspoon salt, and a pinch of pepper. Bring to a simmer and cook, stirring occasionally, until thickened, about 5 minutes. Stir in the cilantro and serve with the chicken.
Menu Suggestions: Rice and beans or refried beans are typical Brazilian side dishes that taste especially good with chicken.
Wine Recommendation: This spicy dish will demolish any subtlety in a wine. Go for something straightforward and gulpable: a fresh white wine such as a pinot bianco from northern Italy, a slightly chilled red such as Beaujolais from France, or a beer.