Bring water to boil then add lentils, garlic powder, thyme and salt. Cook it over a slightly low heat until the water is dissolved or lentils are cooked.
Turn off the heat and let lentils cool down. Refrigerate for at least half hour.
In a medium size mixing bowl add lemon juice, Dijon mustard, garlic, black pepper, red wine vinegar and oregano. Mix well.
Add the cucumber, tomatoes, olives, red onion, parsley, feta crumbles and cooked lentils. Mix well together.
Serve chilled!
Notes
Note: Brown lentils can be used instead of black lentils. Use 1½ cups water if using brown lentils.