Make the chile vinegar: Combine the vinegar, sugar, a pinch of salt and 1 tablespoon water in a very small microwave-safe bowl. Add the jalapeño and microwave until bubbling, about 30 seconds. Let stand while you prepare the succotash.
Put the lima beans in a medium saucepan and cover with water by a couple of inches. Bring to a boil, then boil for 3 minutes. Reduce the heat to a low simmer and cook until tender, about 12 minutes, then drain.
Melt the butter in a large skillet over medium heat. Add the onion and cook, stirring occasionally, until soft and translucent, about 8 minutes. Add the corn, garlic and 1/3 cup water and cook, stirring occasionally, until the corn is tender, about 10 minutes. Stir in the lima beans, tomato and basil. Add as much of the chile vinegar as you like, then serve.