Halve the kielbasa lengthwise and slice into 1/2-inch pieces. Heat a large skillet over medium heat with 1/2 tablespoon oil. Add kielbasa and cook until browned, about 3 minutes per side. Remove and set aside.

In the same skillet, add the remaining oil and cook the chopped onion until softened, about 3 minutes. Add minced garlic and cook for another minute.

Add the chopped cabbage, salt, and pepper. Toss well, cover, and cook, stirring every 4-5 minutes, until cabbage is wilted, about 12 minutes.

Stir in the red wine vinegar, reintroduce the cooked kielbasa, stir to combine, and cook for another 3 minutes until heated through and tender. Taste and adjust seasoning if needed.