Preheat a grill on high with a heavy bottomed skillet on the grate.Add the chorizo to the pan, and cook until sausage begins to brown. Add bell peppers and garlic; sauté until softened. Add clams, pour beer over. Cover skillet and allow to cook until clams have begun to open, 5-7 minutes. Carefully remove cover, add tomatoes, re-cover. Dish will be done when clams are fully open. Discard any that have not opened. Garnish with fresh basil, serve with crusty bread.