Preheat oven to 180°C. Place baguette on an oven tray, drizzle with olive oil, season with salt and bake until crisp and golden brown (12-15 minutes).
For crab mayo, toss ingredients in a bowl to combine and season to taste. Refrigerate until required.
For avocado purée, blend ingredients in a small food processor, scraping down sides occasionally, until smooth and creamy. Season to taste and refrigerate until required.
Spread a small amount of avocado purée on crostini, spoon crab mayo on top and serve topped with freshly ground pepper.
