Cut the pork crosswise into 1-inch pieces; flatten each piece to 1/2-inch thickness using fingertips. Combine flour, salt, and pepper in a large zip-top plastic bag; add pork to bag. Seal and shake to coat.
Heat oil in a large nonstick skillet over medium-high heat. Add pork; cook 4 minutes on each side or until browned. Remove pork from pan; keep warm.
Add shallots to pan; cook 2 minutes or until lightly browned. Stir in wine, juice, mustard, and tarragon, scraping pan to loosen browned bits. Bring to a boil; reduce heat, and simmer 2 minutes. Serve with pork.