In a sauté pan over medium heat, add 2 tablespoons oil and chopped garlic. Cook for 1–2 minutes, just until garlic is fragrant and tender. Add Rainier cherries and bell peppers; remove from heat. Transfer to a medium bowl and stir in vinegar, plus half of the parsley and basil. Allow to rest 10 minutes. Add a few grinds black pepper and salt to taste. Set aside. (This can be made up to an hour ahead. Bring to room temperature before serving.)

In a medium saucepan, combine quinoa and water plus a pinch of salt; bring to a boil, reduce heat, cover, and simmer 12-15 minutes. Turn off heat and let pot sit, covered, for 5 more minutes.

Meanwhile, in a large sauté pan over medium-high heat, cook sliced onion in remaining 1 tablespoon oil, stirring frequently, until golden brown but still firm, 7-8 minutes. Add Bing cherries, turn heat to low, and cook 5-6 minutes. Add cooked quinoa and red pepper flakes; salt to taste.

Preheat grill to medium. In a small bowl, combine remaining parsley and basil with mustard. Gently rub mixture on both sides of salmon fillets, and then season with salt and pepper. Lightly coat fillets with cooking spray and grill each side about 3-4 minutes. Remove and serve atop quinoa mixture, topped with cherry relish and garnished with green onion ribbons.