It's dinner time!

Ingredients

• ½ cup plain yogurt
• ½ cucumber - peeled, seeded and finely chopped
• ½ teaspoon chopped fresh dill, or to taste
• 2 tablespoons olive oil
• 3 large cloves garlic, minced
• 1 large red onion, thinly sliced
• 1 pound ground beef
• 1 pinch dried oregano, or to taste
• 2 stalks celery, chopped
• 1 bunch fresh spinach, cleaned and stemmed
• ½ cup sliced fresh mushrooms
• 5 pita breads, warmed
• ½ cup banana pepper rings
• 2 tomatoes, cut into wedges