Prepare the Steak Marinade:
In a small bowl, mix olive oil, garlic powder, paprika, thyme or oregano, salt, and pepper.
Rub the marinade evenly over the steak and let it rest for at least 15 minutes (or up to 2 hours in the fridge).
Cook the Steak:
Heat a grill or grill pan over medium-high heat.
Cook the steak for 3-4 minutes per side for medium-rare, or longer to your preferred doneness.
Remove from heat and let rest for 5 minutes before slicing thinly against the grain.
Prepare the Dressing:
In a small jar or bowl, whisk together olive oil, balsamic vinegar or lemon juice, Dijon mustard, garlic, salt, and pepper until well combined.
Assemble the Salad:
Divide the mixed greens, cherry tomatoes, cucumber slices, red onion, cheese (if using), and almonds or seeds into meal prep containers.
Top each container with slices of steak.
Store and Serve:
Store the dressing separately in small containers to keep the salad fresh. When ready to eat, drizzle the dressing over the salad and toss to combine.