How to Make It
Heat 2 tablespoons oil in an uncovered pressure cooker over medium-high. Sprinkle steak with 2 teaspoons salt. Working in batches, sear steak pieces until well browned, 2 to 3 minutes per side. Transfer to a medium bowl. Add 1 onion half and 1 bell pepper half to pressure cooker and cook, stirring after 2 minutes, until browned in spots, about 5 minutes. Return steak to pressure cooker; add 5 cups water, bay leaf, and 1 garlic clove. Lock lid into place and set pressure to HIGH (15 pounds); bring up to pressure over high heat. When pressurized, reduce heat to medium and cook 20 minutes. Remove from heat, release pressure, and let stand until pressure is completely released.
When pressure cooker unlocks, transfer steak to a bowl; cool 10 minutes. When cool enough to handle, shred steak by hand. (The pieces do not need to be uniform.) Return shredded meat to bowl. Pour cooking liquid through a fine wire-mesh strainer into a bowl; reserve 2 cups liquid. Discard solids and remaining liquid.
Thinly slice remaining onion and bell pepper halves. Heat remaining 1/4 cup oil in a large, high-sided skillet over medium. Add sliced onions, peppers, and remaining 2 garlic cloves to skillet. Cook, stirring often, until onions are translucent, about 10 minutes. Stir in cumin and oregano. Add wine. Bring to a simmer; add shredded steak and remaining 1 1/2 teaspoons salt. Fold to incorporate with vegetables.
Simmer until meat is warmed through, about 5 minutes. Add tomatoes and 2 cups reserved cooking liquid. Bring to a simmer, stirring. Cover and reduce heat to medium-low. Gently simmer, stirring every 5 minutes, until meat is tender and liquid is thickened, about 20 minutes. If necessary, uncover and cook several minutes to thicken sauce.