Preheat the oven to 400°F (200°C).
Place the salmon fillets on a baking sheet. Season with salt and pepper, then brush each fillet generously with teriyaki sauce.
Bake the salmon in the preheated oven for about 12-15 minutes, or until cooked through and flaky.
While the salmon is baking, prepare the rice according to package instructions (or use a rice cooker).
In a non-stick skillet, heat the olive oil over medium heat. Add the sliced cucumber and sauté for 2-3 minutes until slightly softened, adding a pinch of salt and pepper.
Once the salmon is done, remove it from the oven and let it rest for a couple of minutes.
To assemble the bowls, place a serving of rice at the bottom of each bowl. Top with a piece of teriyaki-glazed salmon, sautéed cucumber, and sliced avocado.
Sprinkle sesame seeds and chopped green onions on top for added flavor and crunch, if desired.