To small saucepan, add coconut oil and lavender. Place over low heat and warm until coconut oil is melted. Remove saucepan from heat and set aside for 10 minutes.
Into medium bowl, strain lavender-infused coconut oil and add 1/2 cup tahini, maple syrup, cacao powder, and salt, if using. Stir with spoon to combine thoroughly.
Line loaf pan with parchment paper; pour in fudge mixture. Drizzle top with remaining 1 Tbsp tahini and garnish with cacao nibs, lavender buds, sesame seeds, and salt, if desired. Freeze for at least 2 hours, uncovered, or 8 hours, covered.
Before serving, remove from freezer and let sit for 5 minutes at room temperature to soften slightly. Slice into 24 pieces and enjoy immediately. Store any remaining fudge in an airtight container in the freezer for up to 1 month.