Heat oven to 400 degrees.
Line baking sheet w/ foil.
Put diced beets into a medium sized bowl, and mix a little olive oil, 4 garlic cloves, salt & pepper to taste, old bay, to taste. Stir to combine.
Add to one side of baking sheet. Put in oven and bake/set timer for 50 minutes.
Meanwhile, pat dry salmon on cutting board and season.
When there are 12 minutes left on the clock, pause your timer, and take sheet pan out. Stir up beets a bit. Spray other half of the baking sheet and add salmon. Put back into the oven for the remaining 12 minutes, until salmon and beets are fully cooked. Take out of oven and serve with Spinach and Beet Greens.