Place the walnuts on a baking sheet, and toast in the oven for about 10 minutes, or until they are lightly golden.
While the walnuts are in the oven, prepare the asparagus by cutting off the bottom ends, which are quite fibrous and tough (See the Tips section below, for an easy method). Next, cut the remaining asparagus into thin, angled slices.
Put the lemon zest and juice in a bowl. Add the hot chili flakes, salt, avocado oil and olive oil.
Add the parmesan cheese and mix well.
Add the asparagus slices to the bowl along with the toasted walnuts. Mix the salad gently but well using a rubber spatula.
Decorate the salad with the mint leaves and serve immediately.