Start by heating olive oil in a skillet over medium heat. Add minced garlic and chopped spinach, cooking until the spinach is wilted and moisture evaporates. Remove from heat and allow it to cool slightly before mixing in cream cheese, feta cheese, lemon zest, lemon juice, dill, salt, and pepper. Ensure that all ingredients are well combined for a creamy filling.

Lay the salmon fillet skin-side down on a clean surface or cutting board. Gently press down on the fillet to flatten it slightly if needed. Spread the prepared filling evenly over the top of the salmon, leaving about an inch around the edges free of filling to prevent overflow when rolling. Carefully roll the salmon away from you into a tight log shape.

Once rolled tightly, use toothpicks or kitchen twine to secure both ends of the pinwheel tightly. This step is crucial as it keeps everything intact during cooking. You can also slice off any uneven ends if desired for a more polished look.

Preheat your oven to 375°F (190°C). Place your secured salmon roll on a baking sheet lined with parchment paper or greased lightly with oil. Bake in the preheated oven for about 18 minutes or until cooked through and flaky in texture.