Slow Cooker Steak Fajitas

Ingredients

• 4 cloves garlic (minced)
• 1 teaspoon cumin
• 1 teaspoon chili powder
• 1 tablespoon lime juice
• 2 tablespoons fresh cilantro
• 1 pound flank steak
• 1 large sweet onion (sliced)
• 3 bell peppers (seeded, sliced)
• 4 8-inch whole-wheat tortillas
• 1 cup shredded lettuce
• 1 avocado (sliced, for serving if desired)
• 1/4 cup plain Greek yogurt (for serving if desired)
• 2 cups diced tomatoes
• 1/2 cup diced sweet onion
• 1/4 cup chopped cilantro
• 1 jalapeño (seeded, diced)
• 1 clove garlic (minced)
• 1/2 teaspoon salt