Heat 1 tablespoon oil in large nonstick skillet over medium-high heat until just smoking. Cook sausages, rolling occasionally, until browned all over, about 10 minutes. Transfer to plate and let cool 5 minutes. Cut sausage in half crosswise.
Add grapes and remaining oil to empty skillet and cook until beginning to brown, about 5 minutes. Stir in water and simmer, using back of spoon to crush some grapes, until grapes have softened and sauce is slightly thickened, about 5 minutes.
Return sausages to pan and simmer until cooked through, about 5 minutes. Stir in vinegar and season with salt and pepper.