Preheat oven to 425. Meanwhile drizzle olive oil in bottom of large skillet and heat until hot,Salt and pepper the pork tenderloin and place in pan to brown (turning often to brown all sides) Your not cooking meat, just browning it to hold in juices
When pork is browned, remove from pan and place in a baking pan, place in oven and bake for 30 minutes or until meat reaches internal temperature of 160. by testing with meat thermometer
Remove from baking pan and let cool slightly. Cut into 1/4 inch slices.
Combine orange juice and mustard and dividing evenly in 6 small bowls and set aside.
Arrange salad grees evenly on 6 serving plates.
Top with pork, oranges and french fried onions.
Garnish each salad with bell pepper and serve with small bowls of mustard dressing.