1. Place first 8 salsa ingredients in a food processor; pulse until chunky. Add remaining salsa ingredients. Season.
2. Coat a saucepan with cooking spray; saute the onion for 5 minutes, stirring frequently. Add potatoes, mushrooms and garlic; cook 10 minutes. Add lentils and stock; cook 25 minutes. Remove from heat; fold spinach, oregano and chile flakes into the mixture. Add feta.
3. Preheat oven to 425 degrees F. Roll 2 tablespoons of the mixture into each tortilla and place seam side down in a lightly sprayed dish. Bake 20 minutes, until crispy. Serve with salsa. Garnish with cilantro and radishes.