In a sauté pan over medium heat, add oil.
Add all the vegetables along with salt, and sauté for approximately 7-10 minutes. When the vegetables have been cooked, remove from heat and set aside.
Meanwhile, toast the bread slices, we grilled ours in a Panini press.
Apply butter on one side of 4 slices. Place one slice of the cheese on top of each of the buttered side.
Apply red chili paste on one side of the remaining 4 slices. Add 3 tablespoons of the vegetable mixture on top of the 4 slices (on top of the red chili paste applied side).
Prepare the sandwiches by placing the cheese slices on top of the vegetables. Serve.