Other 'hot' spices

The first that come to mind are mustard seeds (white, yellow and black, the last the most pungent), peppercorns (all colors), ginger and horseradish.

All of them provide hotness to some extent, albeit a different hotness than the one provided by chili's. Just think about the intensity of wasabi to give you an idea of how "hot" it can get.

Turns out wasabi is actually a root, (I thought it was a paste of several ingredients, you learn something new everyday).

So add wasabi to the list of ingredients.

"Hotness" is a quite vague description which can be caused by a number of chemical compounds and is percieved by various receptors.

• Chili peppers (capsicum) contain the alkaloid capsaicin. If your restaurant insisted that there were no chilis included, there is a slight possibility that they used it under another name (ethnic restaurants or other regions of the world come to mind) e.g. "pereroni" or "paprika".
  (Not that I am implying anything here!)
• Black pepper (piper nigrum) and long pepper contains another alkaloid, the piperine, which gives the seeds their hotness.
• Ginger contains gingerol, which is chemically similar to capsicain and piperine and can be very hot, especially in dried ginger, which loses a lot of the lemony-freshness and gains hotness due to chemical processes that change gingerol into shoagol, which is about twice as "hot". Shoagol has about 160,000 SHU on the scoville scale - more than piperine, less that capsicain.
• Sichuan pepper (no relative despite the name) creates a less-hot-more-numb-to-tingling feeling.
• Mustard and horseradish (and to a lesser extent radishes, cress and other cruciferous plants / brassicaceae) contain glucosinolates, which we percieve as pungent, sharp or hot. An extreme example for glucosinolate-hotness is wasabi.
• Raw garlic and raw onions contain allicin (or, in onions, isoalliin) that has a sharp/biting/hot taste and which contributes to the percieved hotness of fresh garlic and the teary-eyed effect when chopping onions. Interesting fact: Allicin binds both to the receptors that percieve the capsicain-hotness and those for mustard-hotness.
• Cinnamon contains an aromatic essential oil with cinnamaldehyde as main component. The essential oil is very hot, hence cinnamon can taste very hot, especially in "generous" doses.

Ground cumin can be quite hot. It is used in Mexican and Asian cuisines, though I usually see chili peppers in the dish as well.

Galangal has an interesting heat to it. You can buy it fresh or dried at Chinese or Vietnamese grocery stores. All four species of galangal are in the Ginger family, so expect similar, yet distinctly different tastes. Fresh is hotter and fuller than dried.