Preheat the oven to 450℉/232℃.
Heat olive oil in a saucepan and add the chopped red onions. Stir for about 8 minutes until soft and slightly browned.
Add the chopped garlic and stir until fragrant. Take the pan off the heat and let it cool.
Cut the bell peppers and jalapenos in half lengthwise. Discard the seeds and membranes.
Place the pepper and jalapeno halves, skin side up, on a foil-lined baking sheet. Flatten the pepper halves with your hand.
Drizzle or lightly brush the peppers with oil and roast them for 25 minutes. They will begin to char slightly.
Remove from the oven and immediately place only the red bell peppers in a bowl and cover with a kitchen towel. This will help the skin to come loose. Let it sit for 10 minutes, then peel and discard the skin.
Add the roast peppers, jalapenos, sauteed onion and garlic, tomato paste, lemon juice, water, salt, and pepper to a blender or food processor.
Process or blend until smooth or until you reach the desired consistency. Taste test and season with a little more salt and pepper if needed.