To prepare the salsa, preheat oven to 400 F. In a small bowl, combine tomatoes, onion, tomatillos, jalapeño and garlic. Add olive oil, salt and black pepper; toss to coat. Place mixture on baking sheet and roast 15 minutes, until softened and lightly browned. Transfer to a blender and process to a coarse consistency. Place mixture in a bowl and stir in lime juice and cilantro. (Can be kept in the refrigerator, covered, for up to 5 days, and frozen for up to 3 months.)
To make the burrito, brush a large skillet with 1 teaspoon of the olive oil and set pan over medium-high heat. Add onion and cook 2-3 minutes, until softened, stirring frequently. Add mushrooms and peppers and cook until mushroom liquid is almost evaporated. Add tomatoes and spinach and cook 2-3 minutes, until spinach begins to wilt, stirring frequently. Season with salt. Set mixture aside in a bowl.
In a medium bowl, whisk together eggs and egg whites until blended.
Brush the same skillet with remaining olive oil and set pan over medium heat. Add beaten eggs and cook 1-11/2 minutes, until eggs are scrambled but still wet, stirring constantly. Stir in cooked vegetable mixture. Sprinkle feta cheese over top and season with salt, if desired. Transfer mixture to a bowl and set aside.
Preheat the same skillet over medium heat. Place tortillas in skillet and cook 20 seconds per side, until hot. Put tortillas on a flat surface and spoon 1/2 cup of cooked egg mixture onto center of each tortilla. Drizzle 2 tablespoons salsa over each serving and roll tortillas into 11/2-inch cylinders. Serve immediately, or cover with a clean kitchen towel and place on a baking pan in a 200 F oven for up to 20 minutes. (You can refrigerate the egg mixture for up to 3 days; freezing is not recommended.)
To serve, slice each rolled tortilla in half diagonally and garnish with dollops of salsa and chopped cilantro.