1. Trim fat from tenderloin. Cut tenderloin into 1/2-inch-thick slices; place slices between 2 sheets of heavy-duty plastic wrap, and pound to 1/4-inch thickness, using a meat mallet or rolling pin.
2. Combine flour, salt, and pepper in a large heavy-duty zip-top plastic bag; add pork slices. Seal bag, and shake until pork is coated.
3. Coat a large nonstick skillet with cooking spray; add 1 teaspoon oil, and place over medium-high heat until hot. Add half of pork slices; cook 2 minutes on each side or until browned. Transfer to a serving plate; keep warm. Repeat procedure with remaining 1 teaspoon oil and pork slices; remove skillet from heat.
4. Add lemon juice, water, and capers to skillet; bring just to a boil. Pour mixture over pork slices; sprinkle with parsley.