Roast the Potatoes:
Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a bowl, combine the diced potatoes, half of the red onion, jalapeño, bell pepper, olive oil, paprika, and chili powder. Stir to evenly coat the vegetables.
Spread the mixture out on the prepared baking sheet and season with salt and pepper.
Bake for 20 minutes, remove from the oven, and flip the vegetables. Return to the oven and roast for an additional 10-20 minutes, or until the potatoes are crispy and the veggies are soft.
Prepare the Mustard Tahini Dressing:
While the potatoes are roasting, combine the tahini, mustard, lemon juice, oregano, garlic salt, and pepper in a bowl.
Stir the mixture until well combined, adjusting the seasoning as needed. Add water, a little at a time, until the desired consistency is reached.
Refrigerate the dressing until ready to use.
Massage the Kale:
Place the chopped kale in a large bowl and drizzle with lemon juice.
Massage the kale with your hands for 30-60 seconds, or until the lemon juice is absorbed and the kale has softened.
Refrigerate until ready to assemble the bowls.
Assemble the Bowls:
Once the potatoes are done, sprinkle with additional salt if desired.
In serving bowls, layer the massaged kale, the remaining raw red onion, and the roasted potatoes.
Drizzle generously with the mustard tahini dressing and serve immediately.