Place the watermelon, red onion, cucumber, and feta on a large platter.
Place the pine nuts in a pan over medium-low heat and cook for about 5 minutes stirring and shaking the pan frequently to evenly toast the pine nuts. Once the pine nuts are toasty brown and fragrant, remove them from the heat and sprinkle them on top of the salad.
Garnish the salad with fresh basil leaves.
Add the lemon juice, avocado oil, agave, vinegar, and mustard to a jar with a lid. Secure the lid and shake for 20 seconds.
Pour half of the dressing onto the salad and leave the rest of the dressing to be poured on top of the salad once individually plated.