Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper. Set aside.
In a large bowl, mix the sweet potato cubes with the olive oil, smoked paprika, ground cumin, oregano, and salt, toss to coat. Transfer to the prepared baking sheet and bake for about 25 minutes, or until the sweet potatoes are soft and golden brown. Remove from the oven and drizzle with the balsamic vinegar, toss to coat and set aside to cool.
In the meantime, prepare the dressing: In a small bowl, combine all the ingredients together. Taste and adjust seasonings if needed. If the dressing appears too thick, thin with a couple tablespoons of water.
To make the salad, divide the arugula into 4 serving bowls, or plate. Top with roasted sweet potato, pine nuts, sunflower seeds, and red pepper flakes. Top with the avocado and cucumber slices, and drizzle with the mint yogurt dressing. Garnish with a few mint leaves. Toss to combine and coat the arugula with the dressing. If you prefer, you can also make the salad in one large bowl and then serve.
The salad is best fresh but will keep for up to 2 days covered in the refrigerator