For the dressing, if the Medjool dates are hard, soak them in warm water for 10 minutes until softened. Drain water and place dates in a food processor or stand blender.
Add green onion, garlic, lemon zest and juice, parsley, vinegar, and mustard. Blend until smooth.
With food processor running on low speed, slowly add the olive oil in a steady stream until incorporated. Taste and season with salt and pepper, as needed. Set aside.
Combine shallots, vinegar, maple syrup, and salt in a small bowl or measuring cup. Stir to coat shallots and set aside.
Preheat a grill or grill pan over medium-high heat. While the grill heats up, pat steak dry with paper towels and season on both sides with salt, garlic powder, and pepper.
Lightly grease the grill and add steaks, cooking until desired doneness, about 4-5 minutes per side for medium-rare. Remove to a plate and allow to rest for 10 minutes. Set aside.
Place beans, corn, roasted red peppers, sun-dried tomatoes, dates, parsley, and mint in a large serving bowl. Drain shallots and add to the serving bowl, along with the dressing, and toss to combine. If desired, transfer salad to a large platter or leave in the bowl.
Thinly slice steak against the grain. Serve on top of the salad and enjoy!