Heat a large Dutch oven over medium-high heat until hot. Add kielbasa; sauté 10 minutes or until done. Remove kielbasa from pan. Heat oil in pan over medium-high heat until hot. Add onion and garlic; sauté 5 minutes. Add milk, potato, salt, and pepper; bring to a boil. Cover, reduce heat, and simmer 30 minutes or until potato is very tender.
Remove the potato mixture from heat, and beat at medium speed of a mixer until smooth. Stir in the kielbasa and kale, and cook for 10 minutes or until thoroughly heated.