In a large skillet over medium-high heat, add 1 tablespoon oil. Add the shrimp and sprinkle with ½ teaspoon salt. Cook for 1-3 minutes (depending on how large the shrimp are) or until the shrimp are almost cooked through all the way and light golden on the bottom. Flip and cook for 1 more minute or until cooked through (no longer translucent in the center). Transfer the shrimp to a plate.
To the skillet over medium-high heat, add the remaining 1 tablespoon oil, veggies, garlic, and remaining ½ teaspoon salt. Stir everything together and let cook, stirring occasionally, for 2-5 minutes, or until the veggies are softened.
Stir in the tomato paste and red pepper flakes (if using) and cook for 2 minutes to caramelize the tomato paste, stirring occasionally. Turn off the heat and stir in the water and shrimp.
Remove about 2 tablespoons of liquid from the pan and add it to a small bowl with the miso paste and mash it up with a fork to dissolve. Add it back into the pan (scrape out every last bit) along with the butter. Stir until the butter is melted and incorporated into a silky sauce (turn the heat back on if the butter is not melting). If your sauce has reduced too much/you want it saucier, just add a splash of water to thin it out.
Serve over a bed of warm rice and top with cilantro, almonds, and a squeeze of lemon.