Halve baguette lengthwise and cut into 4 pieces. Season tomato puree with salt, pizza seasoning and garlic, spread on baguettes and top with ham, cucumber slices and onion rings.
Spread with cooking cheese and arrange on a lined with parchment paper baking sheet. Bake in preheated oven at 270°C (approximately 525°F) for about 5 minutes, watching carefully. Remove from the oven and serve immediately