Preheat the oven to 400°F. Line a rimmed baking sheet or large rectangular baking dish with parchment paper (this is optional; it will make cleanup easier).
Thickly slice the date halves (you should have a scant ½ cup). Transfer to a small bowl and toss with the olive oil, almonds, mint, jalapeño, cumin, salt, and cinnamon. Arrange the salmon on the prepared baking sheet and season with salt and pepper. Brush the silan on the salmon and use lightly oiled hands to spread the date-almond mixture all over the top.
Roast until the almonds are lightly golden, the dates are caramelized, and the salmon is medium-rare in the center (120°F if you are using a thermometer), 12 to 14 minutes. Remove from the oven and halve the lemon, squeeze one half right on top. Halve the lemon, squeeze one of the halves on top of the salmon and couscous. Serve with salad and couscous, garnished with more mint.