Melt butter in a large skillet over medium-high heat. Add venison and cook until no longer pink, stirring to break up. Stir in garlic and onion, and continue cooking until the onion has softened and turned translucent, about 2 minutes.
Meanwhile, melt remaining 2 tablespoons butter in a saucepan over medium heat. Stir in Spanish rice mix, and cook until lightly golden, about 5 minutes. Stir in cooked venison, water, tomatoes, salsa, and kidney beans; bring to a boil, then reduce heat to medium-low and simmer for 15 minutes. Stir in corn, and continue cooking until the rice is tender, about 5 minutes.
