Spray the red peppers with oil and place directly in the air fryer basket.
Set air fryer to 400F for 10 minutes.
At the end of the cook time, add the walnuts to the basket, around the red peppers. Set air fryer to 400F for 5 minutes.
Remove the peppers and walnuts. Place peppers into a plastic zip top bag and let them rest while you get the other ingredients together, about 5-10 minutes.
Place softened peppers, walnuts, lemon juice, salt, cumin, and 1/2 teaspoon pepper flakes in the bowl of a food processor and puree until you get a smooth mixture.
Tip the dip into a bowl and make an indentation in the middle. Pour in the olive oil and garnish with remaining pepper flakes. Serve with toasted pita chips or raw vegetables like cucumber, carrots, zucchini slices or cauliflower.