Remove the thick center stems from each kale leaf, stack several leaves together, roll them tightly, and slice into thin ribbons. Chop those ribbons crosswise into small, bite-sized pieces.

Transfer the chopped kale to a large mixing bowl, add a pinch of salt, and massage the leaves with your hands for about two minutes.

Chop the tomatoes, cucumber, bell pepper, and red onion into similar-sized small pieces.

In a small bowl, whisk together olive oil, lemon juice, Dijon mustard, honey, minced garlic, salt, and pepper until emulsified.

Add all the chopped vegetables to the bowl with the massaged kale, pour the dressing over everything, and toss thoroughly to combine. Fold in the crumbled feta cheese and toasted sunflower seeds before serving.