Preheat the oven to 175°C and line a large baking sheet or two smaller baking sheets with parchment paper.
In a large bowl, combine the sunflower seeds, pumpkin seeds, sesame seeds, flaxseed meal, almond flour, sea salt, garlic powder, and dried thyme until evenly mixed.
Add the olive oil and water to the dry ingredients and stir well. Let the mixture stand for 10 minutes so the flaxseed meal can absorb moisture and help bind the dough.
Spread the seed mixture onto the prepared parchment in a thin even rectangle about 3 millimeters thick. Use a spatula or the back of a spoon to press it flat, and score it lightly into cracker-sized pieces for easier breaking after baking.
Bake for 30 to 35 minutes, rotating the pan halfway through, until the crackers look dry, lightly golden, and firm to the touch.
Cool the crackers on the pan for 10 minutes, then transfer them to a rack and let them cool completely so they become crisp. Break along the scored lines into rustic pieces.
While the crackers cool, prepare the dip by stirring the honey and Dijon mustard together in a small bowl until smooth.
Wash and dry the grapes, cucumber, and cherry tomatoes. Slice the cucumber, cut the cheddar, wedge the brie, and separate the prosciutto and salami into easy-to-grab portions.
Arrange the cheeses, cured meats, grapes, cucumber, cherry tomatoes, olives, almonds, dried apricots, and honey-mustard dip on a large board or platter, spacing the items around the surface.
Tuck the cooled seed crackers into open spaces around the board, keeping some upright and some flat for visual variety. Serve immediately or cover and refrigerate the board components separately until ready to assemble.