To make avocado cream, place the first 5 ingredients in a food processor and pulse until smooth. The mixture should be fairly thick. Transfer to a bowl, cover and refrigerate.
Preheat the oven 375 degrees F. Line a baking sheet with parchment paper. Set on the squares of salmon. Drizzle each piece of salmon with a little olive oil; season with Cajun spice or seasoning salt. Bake the fish 10 minutes, or until just cooked through.
Spread the bottom of each slider bun with some of the avocado cream. Set a lettuce leaf on each bottom bun, and then a piece of salmon. Top the salmon with some more of the avocado cream, and then a cherry tomato slice. Set on the top buns and serve.