Heat a large skillet with deep sides over medium heat. After 2 minutes, add oil, onions, and salt. Cook, stirring often, until onions have softened and are turning translucent (about 5 minutes.) Add ginger and garlic. Cook, stirring often, until fragrant (about 1 minute.)
Add potatoes and place lid over skillet to cook the potatoes quicker. Stir every 3-4 minutes until almost fork tender. Add eggplant, zucchini, carrots, and bell pepper. Cook, stirring occasionally for another 5 minutes. Add curry paste and cook another 2 minutes.
Add oat milk and stir to combine. Stir in turmeric powder.
Reduce heat as necessary to maintain a gentle simmer and cook until the vegetables have softened to your liking, about 7 to 10 minutes, stirring occasionally. In a small bowl, whisk together the arrowroot flour with water until combined. Slowly pour in the arrowroot slurry while whisking. You may not need all of it. Stir for about 1 minute longer.
Remove pot from the heat and stir in coconut aminos and rice vinegar. Taste for additional seasoning.
Serve warm with cooked cauliflower rice or white rice. Garnish with red pepper flakes, chopped cilantro or chili oil.