Pre-heat oven to 425F. Place the diced sweet potatoes on a large sheet pan, lined with parchment paper.
Drizzle with olive oil over the sweet potatoes. Sprinkle with the cumin and coriander. Add the Kosher salt to taste all over.
Roast the sweet potatoes in the oven for about 25 minutes, turning half-way.
While the sweet potatoes roast, add the drained and rinsed black beans to a large bowl with the chopped spinach and crumbled feta cheese. Toss to combine and set aside.
Make the avocado dressing: blend all ingredients in a blender or food processor until emulsified. If too thick, you can thin out with a little water or olive oil.
Once sweet potatoes are cooked through, remove from the oven and make up the bowls: add the spinach, feta and black bean mixture to serving bowls. Top with the sweet potatoes, diced cucumber and halved cherry tomatoes.
Add some of the avocado dressing on top and some fresh ground pepper. Dig in!