For the salsa: Peel and trim the ends from each orange. Using a paring knife, cut along the membrane on both sides of each segment. Free the segments and add them to a medium bowl. Add the olive oil, lemon juice, parsley, scallions, mint, capers, orange zest, lemon zest, and red pepper flakes. Toss lightly and season with salt and pepper, to taste. Set aside.
For the salmon: Put a grill pan over medium-high heat or preheat a gas or charcoal grill. Brush the grilling rack with vegetable oil to keep the salmon from sticking. Brush the salmon on both sides with the agave nectar and season with salt and pepper, to taste. Grill until the fish flakes easily and is cooked through, about 3 to 4 minutes on each side. Transfer the salmon to a platter and allow to rest for 5 minutes.
Spoon the salsa verde on top of the salmon or serve on the side as an accompaniment.