Cook onion on medium-low heat until translucent. Add rhubarb and cook until rhubarb becomes soft and begins to breakdown. Season with salt and pepper. Remove from heat and let cool.

Combine onion-rhubarb mixture with ground chicken and garlic chives.

Form into patties and refrigerate until ready to grill.

Before grilling, season both sides with salt and pepper.

Cook on a grill pan or frying pan on medium heat until browned on both sides and center is cooked through, about 5 minutes each side.