Heat a non-stick skillet over medium heat. Add the walnuts and toast for 2-3 minutes until just warmed through and lightly toasted, taking care not to brown.
Place the walnuts in the base of a food processor and pulse until very finely chopped.
Add the kale, garlic, lemon juice, zest, and salt to the walnuts and pulse again until the kale is broken down.
With the motor running, add the olive oil and puree until creamy and smooth. Taste and add more salt as desired.