Sort and rinse the lentils. Place in a saucepan and cover with water by 3 inches (the length of your index finger) and bring to a gentle boil. Immediately reduce to a simmer and cook until tender all the way through about 20 minutes. Don’t overcook to avoid mushy texture. Drain.
Toss the hot lentils with the red wine vinegar, salt, and fresh-ground black pepper. Let sit for 5 minutes.
Taste and adjust seasonings if needed. Then gently add the olive oil, red peppers, scallions, cherry tomatoes, feta and parsley.
Ladle each serving of the room temperature lentil mixture into a large lettuce leaf and garnish with the above suggestions to your liking. Serve immediately.