Begin by patting dry 1 block of extra-firm tofu and then cutting it into 1" cubes. Gently toss the cubes with 1-2 T. vegetable or peanut oil and a generous dusting of finely ground sea salt. Place in a single layer on a baking sheet and roast at 400 degrees F. for 15 minutes. Flip the cubes and cook for another 10-15 minutes, until the tofu is somewhat crispy on both sides and lightly browned. remove from oven and set aside.
Next, in a medium-size bowl, stir together 3/4 cup natural ketchup, 1/4 cup rice or white vinegar, 2 T. tamari or soy sauce, 1 T. sriracha and 1/3 cup brown sugar. Set aside while you heat 2 T. peanut or vegetable oil in a large non-stick skillet over a medium-high flame. When the oil is very hot but not smoking toss in 6-8 whole dried red chilies. Stir for a moment as the chilies darken. Throw in 1 thinly sliced onion, 2 cloves sliced garlic, 1 T. grated ginger and 1 thinly sliced yellow or red bell pepper. Stir constantly until the peppers begin to soften. Add the roasted tofu and the mixed sauce. Cook for a minute or two ensuring the sauce thickens quickly. Finally, sprinkle in 3 T. sesame seeds.
Serve hot with rice and steamed broccoli or another green vegetable.