Preheat the grill, set a grill pan on the stove (without turning it on), or set up the broiler pan in your oven.
Place the cubed beef in a bowl and season with a drizzle of olive oil, 1/2 teaspoon salt, 1/2 teaspoon ground black pepper, 1 teaspoon garlic powder, and 1 teaspoon paprika. Toss to coat. Toss the veggies with a little olive oil as well to prevent sticking on the grill, and season with salt and pepper.
Thread the beef, bell pepper, onion, and zucchini onto the skewers, alternating between items. You should fill about 16 skewers. Cook on the grill until the veggies are charred and the meat is cooked through, OR cook on the grill pan or under the broiler, about 12-15 minutes total, turning occasionally to cook all sides.
Meanwhile, put the parsley, cilantro, lemon juice, garlic, red pepper flakes, oregano, vinegar, shallot, and extra virgin olive oil in a mini food processor or blender. Blend or pulse until a chunky chimichurri sauce is formed. Serve the skewers with a liberal drizzle of chimichurri. Goes well with wild rice blend or other whole grain side.