ROAST: Preheat the oven to 400 F / 205 C. Line a baking sheet with parchment paper and place the salmon, skin side down, onto the sheet. Drizzle the salmon with olive oil and brush it over to coat evenly, then season to taste with salt & pepper. Slide the salmon into the oven and cook until the salmon is opaque on the outside, just beginning to flake and still just a tad pink in the middle, about 8 - 12 minutes, depending on the thickness of the fish. Remove from the oven and let cool on the tray just enough to handle. BLEND: Add the tahini & lemon juice to a mini food processor and whizz until thickened but combined. Slowly drizzle in the cold water a tablespoon / 15 ml at a time, blending until smooth each time. Remove the lid & blade from the food processor and add the remaining dressing ingredients, stirring to combine. Adjust the salt and pepper, to taste, and additional water only if you would like a thinner dressing. Set aside. CRISP: Cook the bacon in a skillet until crisped to your liking, then remove to a paper towel lined plate to cool. Chop into bite size pieces. ASSEMBLE: Divide the ingredients between plates or pile onto a platter. Start with the chopped romaine & sliced cucumbers. Remove the now cooled salmon from its skin and gently flake the fish over the top of the greens. Scatter over the halved tomatoes, sliced radishes & onions. Top with the crispy bacon, avocado and sprinkle over any garnishes you like. Drizzle with the tahini ranch and serve immediately.