Preheat the oven to 200C/400F. Peel and cut the sweet potato into cubes. Add into a mixing bowl and coat with the olive oil, cumin, salt and pepper. Place in an oven tray and bake for around 25-30 minutes.
Heat in a medium-size pan double the amount of water than quinoa and add the quinoa. When the water starts boiling, reduce the heat to really low and leave it cooking until all the water is absorbed. Add to a big salad bowl and leave it to cool for a few minutes.
Add to the salad the black beans, previously rinsed, the baked sweet potato and the avocado cut into cubes.
Toast the cashews in a small frying pan. Don't add any oil as it's not needed. Simply heat a small pan on medium heat, add the cashews and keep turning them so they don't burn on one side. When they start to brown, you can add them to the salad.
For the vinaigrette, mix in a bowl the olive oil, lemon juice, tahini and maple syrup. Finely chop the mint leaves and add them to the dressing. Stir well with a fork or a small whisk until all the ingredients are perfectly combined and add to the salad.
Sprinkle some finely chopped mint leaves to the salad and mix all the ingredients. Serve and enjoy!