Mix the fajita seasoning. In a small bowl, combine chili powder, cumin, smoked paprika, garlic powder, oregano, salt, and black pepper.
Season the beef. Pat the sliced steak dry.
Toss with half the seasoning, 1 tablespoon olive oil, and the juice of half a lime. Set aside while you prep the veggies.
Prep the dressing. Whisk Greek yogurt, olive oil, lime zest and juice, grated garlic, cilantro, honey, salt, and pepper until smooth. Thin with a splash of water if needed.
Taste and adjust salt or lime.
Sear the veggies. Heat a large skillet over medium-high until hot. Add 1/2 tablespoon olive oil. Add peppers and onions with the remaining seasoning.
Cook 4–6 minutes, tossing occasionally, until lightly charred and crisp-tender. Transfer to a plate.
Sear the beef. Add the remaining 1/2 tablespoon oil to the hot skillet. Arrange the beef in a single layer.
Sear 1–2 minutes per side until browned and just cooked through. Squeeze in the remaining lime juice and toss. Remove from heat.
Assemble the bowls. Divide salad greens among bowls.
Top with tomatoes, black beans (if using), peppers and onions, sliced beef, avocado, cilantro, and cheese. Sprinkle pepitas for crunch.
Dress and serve. Drizzle the creamy lime-cilantro dressing over each bowl. Serve with extra lime wedges and a pinch of salt if needed.