In a large bowl, submerge the dried black eyed peas in water for 8 hours or overnight. Rinse and drain them. Set aside.
Preheat the Instant Pot using the SAUTE function.
When the display panel says HOT, add the onion and bell pepper. Cook, stirring frequently, until the vegetables brown and begin to stick to the bottom of the pot, about 6 minutes.
Stir in 3 tablespoons of water and continue to cook, stirring, until onion is soft and lightly browned. Stir in garlic, dates, vinegar, parsley, oregano, chili powder, sea salt, and red pepper flakes. Cook 1 min, stirring continually.
Add the soaked and drained black eyed peas to the pot, along with the remaining 4 cups of water and tomato paste. Place the lid on the cooker and make sure the pressure knob is in the SEALING position. Using the display panel select the CANCEL button. Then the MANUAL/PRESSURE COOK function, high pressure, and use the +/- buttons until the display reads 9 minutes.
When the cooker beeps to let you know it’s finished, switch the pressure knob from the sealing to the venting position. Remove the lid, add the baby spinach, and stir until the spinach has wilted. Salt to taste and serve warm.