Preheat oven to 375F and move the rack to the top third of the oven. Line a baking sheet with foil for easy clean-up.
Coat salmon lightly with a bit of olive oil and sprinkle on a bit of garlic powder and salt & pepper. Place salmon in the oven and bake for 10-15 minutes or until it's cooked through and flakes easily with a fork.
Meanwhile, chop your shallot and dill, and mix them into the Greek yogurt. Toast your bread.
Once the salmon has finished cooking, flake it into smaller pieces and squeeze some lemon juice over it. Spread the yogurt mixture onto the bread and top it with your salmon and arugula.
Notes
I wrote this recipe with one person in mind, but it easily doubles.