Chop the cauliflower into roughly 1-inch pieces (see photos). Don't worry about keeping the florets pretty, you are going to pulverize them anyway.
Add about 1/3 (or even 1/4) of your cauliflower to your food processor. Don't try to do too much at once; you will get half mush and half chunks. PULSE the cauliflower in 1-second bursts, until it looks about the size of grains of rice. Repeat with the remaining cauliflower.
In a wide-bottom skillet, melt butter over medium heat. Add the sesame oil. Saute the garlic for about 1 minute, until fragrant.
Add all of the cauliflower rice. It may seem like a lot, but it will cook down.
Stir in rice vinegar, soy sauce, ginger, salt, and sweet chili sauce. Continue to cook the cauliflower until it is tender, about 8-12 minutes.
Remove from heat and stir in the lime juice and cilantro.
Garnish with additional lime and cilantro, if you want.
*Chopped fresh ginger tastes great too. I've tried it both ways. Make sure you taste as you go. My cauliflower was huge, so I added the high end of the ranges given. If you have a smaller cauliflower, go with less. If you don't have a food processor, a cheese grater works. A little messy, but does the job.