Core and dice apples, add to a large mixing bowl. Chop broccoli into smaller, bite-sized pieces; add to apples. Slice grapes in half and dice onion; add both to apples.
Add sunflower seeds, juice from the oranges, cider vinegar, salt, and pepper to the apples; toss to evenly coat.
Drain and rinse chickpeas. Add to a blender with mayonnaise, turmeric, onion powder, minced garlic clove, and remaining salt and pepper.
Pulse until well-incorporated. Continue to blend until your personal desired texture has been reached. Spread onto each of 4 slices of bread, top each with a second slice of bread. Cut in half and serve with salad.