The recipe you will find here: http://runningonbrie.com/2014/04/28/korean-inspired-pork-rice-bowl/ (Korean Pork Rice Bowl recipe)
The author of the linked recipe appears to be substituting in turn for gochujang, which in addition to spice has a bit of a yeasty, fermented flavor not unlike miso (no surprise, since both include fermented soybean). Sambal oelek will be brighter, generally hotter, and looser in texture. It's less of a paste than the chili stuff used here, so the resulting sauce will be a bit thinner once mixed and may not adhere to the pork as well.
If it's all you've got, then substitute away! You'll probably still enjoy the end result. However, if you'd like to get a bit closer, here are a couple things you could try, in descending order of effort:
- Add about 1/2 teaspoon or so of cornstarch to the sauce to thicken and balance the texture of the sambal oelek.
- Add a small dab of miso paste to the sauce (hard to measure exactly, but I'd say 1/2 to 1 teaspoon depending on your brand of miso). This will have a similar thickening effect and get you a little closer to the flavor of the original gochujang paste.
- Head to a local asian market and find yourself some gochujang, then substitute for equal quantity for the chili paste in the recipe. Don't worry about having extra, you could use this in a huge range of asian-inspired marinades or other sauces.
As a final aside that has nothing to do with your question, I just noticed that the author of the linked recipe lists one of the last steps as sauteeing the carrots and bean sprouts together. I'd suggest that you definitely not do this to your poor bean sprouts. Go and cook the carrots, or you could cheat and use the coarse side of a box grater to serve them raw with a much nicer texture. That's what I'd do with a dish like this.
As Richard mentioned, Sambal Oelek is made from fresh chilies and little else, so the flavor will be different.
Conveniently, I happen to have various chili pastes in my fridge and pantry:
- Sambal Oelek (Huy Fong Foods) : chili, salt, distilled vinegar, potasium sorbate and potasium bisulfite as preservatives.
- Red Chili Paste (Thai Kitchen) : red chili, garlic, lemongrass, galangal, salt, onion, kafir lime, coriander, pepper
- Roasted Red Chili Paste (Thai Kitchen) : (ingredient list is so tiny, I can't read it ... I think the second item is garlic ... wow, is that eye strain)
update : and just as I was writing my answer, logophobe posted, suggesting that the substitution was going the other way than I had thought it was, and that this was in turn a substitute for korean chili paste. I don't know if the store bought stuff that I have is fermented or not:
- Hot Pepper Paste, level 3 (Rhee Bros, Inc.) : Red pepper powder, corn syrup, water, red pepper seasoning (red pepper, water, salt, garlic, onion), wheat flour, salt, rice powder, soybean powder, glucost, garlic powder, monosodium l-glutimate
If you want to attempt to appriximate the original recipe, sambal might make for a better base than thai chili paste, but it's going to have a much stronger chili bite to it. A blend of sambal and miso might be a good alternative, or sambal manis, you have it.
To approximate the recipe that you linked to, you'd also need to add garlic and other slides. If you don't have lemongrass, try a small bit of lemon zest. As you likely don't have galangal, substitute ginger.
But even with just sambal and miso, or sambal and garlic, it'll probably come out fine.
Sambal Oelek is made with raw chili peppers and salt, ground together in a mortar. The author of the recipe seems to have used a paste made from smoked chili's out of a jar.
Both will always add chili heat to your dish, but there is a good chance that the taste of the end product will be slightly different.
Given the number of other big tasting ingredients in this recipe I think I would simply go for it.