In a medium pot of boiling salted water, cook tomatillos until tender, 10 to 15 minutes. Drain tomatillos and transfer to a blender; add onion, clove, jalapeno, and water. Puree until smooth. (Use caution when blending hot liquids: Remove cap from lid and cover opening with a dish towel.) Season with salt and pepper. In pot, heat oil over high until shimmering. Add tomatillo mixture and simmer, stirring occasionally, until thickened, 5 to 10 minutes. Remove from heat and stir in cilantro, vinegar, and sugar. Season to taste with salt and pepper.
Refrigerate in an airtight container, up to 1 day.