Prepare the Lentils
In a medium skillet heat a couple tablespoons oil over medium heat and saute the onion and carrot for a minute. Add the celery and fennel. SautÉ gently for 4 more minutes until onion is soft. Add the lentils and stir well. Add the water, 1 tsp of salt and several grinds of black pepper. Mix well and bring to a boil. Reduce heat and simmer partially covered for about 40 minutes or until lentils are tender and liquid is absorbed. Remove from heat and keep warm.
While the lentils are simmering, cook the bacon till crisp, drain and set aside.
While lentils are cooking
Preheat the grill. Season the tenderloin with a generous amount of salt and pepper.
Grill over indirect medium heat for about 15 minute until an instant read meat thermometer reads 145 when pierced into center of meat.
While the meat is on the grill
In a non-reactive saucepan, reduce the wine to about 1/4 cup. Whisk in about 6 tblsp Olive oil and the red wine vinegar. Add the bacon, stir and then pour the mixture over the lentils. Mix well.
Let the meat stand covered with aluminum foil for 5 minutes after removing from grill. Slice.
Put a nice portion of the lentils on a plate and top with sliced pork.