Place tilapia fillets on prepared baking sheet and season both sides with a pinch of salt and pepper. Roast until fish reaches a minimum internal temperature of 145 degrees, 12-15 minutes. Remove from oven and let cool 5-10 minutes. While fish roasts, toast pine nuts.

Heat a large non-stick pan over medium heat. Add pine nuts to hot, dry pan. Stir occasionally until lightly browned and aromatic, 3-5 minutes. Transfer to a plate. Reserve pan; no need to wipe clean.

Halve grape tomatoes. Trim cucumber, halve lengthwise, and cut into 1/4" half-moons. Trim radish, halve, and cut into 1/4" half-moons. Coarsely chop toasted pine nuts. Finely mince garlic. Combine grape tomatoes, cucumbers, radish, 2 tsp. olive oil, 1/4 tsp. salt, and a pinch of pepper in a mixing bowl.

Once tilapia has cooled, transfer fish to another mixing bowl and lightly shred. Add panko, mayonnaise, pine nuts, half the red pepper flakes (to taste) (reserve remaining for garnish), 1/4 tsp. salt, and a pinch of pepper to bowl with fish. Mix until ingredients form a slightly sticky mixture.

Form mixture into four fish cakes, 3/4" thick. Return pan used to toast pine nuts to medium heat with 2 tsp. olive oil. Add fish cakes to hot pan and cook until browned and warm throughout, 3-4 minutes per side. Remove from burner.

Combine sour cream and garlic (to taste) in another mixing bowl. Add a serving of salad to a plate. Place two fish cakes against salad. Serve sauce on the side. Garnish with remaining red pepper flakes (to taste).