I'll take your word on the Dave's Sauce. <smile>
FWIW, khon thai (with khon pronounced kinda like "kawwn") means "Thai person," or "Thai people," but I'm not sure if it's of much use in English conversation. In fact, using it might cause some offense.
You are probably better off with the following request:
"Please have the kitchen make my food Thai-style, or Thai hot."
Or, if you are asked how hot you'd like your food, try:
"Phet Maak." <see footnote 1>
"Please have the cook make my food the way she would eat it."
"Please have the cook make my food the way YOU would eat it."
Now, unless I'm asked, I'm not so concerned with exactly how hot my food is made. I'm happy enough knowing that I'm receiving food which was made in the proper Thai style, with the words "proper Thai style" in 3ft. capital letters.
Me, I'm looking for the food the kitchen serves their Thai patrons, which might be different from the food they'd serve an amped-up, thrill-seeking "foreign" audience. Understand? Yes, sometimes it means that the food is made really spicy, but it might also mean that the food is made more salty, savoury, "funky," etc.
This sort of thing is best captured with the phrase, "aahaan Thai," which means "real, Thai-style food." <see footnote 2>
IMO, non-Thais would be much better off concerning themselves with real, Thai-style food instead of so much heat. If they focused on style, trust me, the heat they're after will still be present. But, only when and where it's called for. 'Cause, when it comes to proper Thai food, heat is only one variable in a very, very complex equation.
And, well, I wouldn't want anyone to miss the forest for the trees. <smile>
<footnote 1> Phet Maak means "very spicy" in Thai, and it's pronounced kinda like "peeht maahk." As if you were stretching out the English words "pet" and "mock" ever so slightly.
<footnote 2> The word "aahaan" in the expression, "aahaan Thai," is pronounced kinda like "ahhh-haahn." Anyway, it's a particularly useful expression for English speakers. To say, "mai aahaan farang," (with "mai" pronounced kinda like "may," and "farang" pronounced kinda like, "fuhh-raahng," but quickly) means that you don't want your food made in a "foreign" style. It implies that you want "real deal" Thai food. And, I ask you: how can it get any better than that? <smile>