Heat a big pan with sides over medium-low heat. Add the oil. When it is shimmering, add the onions, green peppers and jalapeƱos. Cook until the onions are translucent, 3 or 4 minutes.
Add the garlic, chili powder, paprika and salt. Cook until the garlic is fragrant, 1 to 2 minutes.
Add the tomato paste and mix the tomato paste into the onions and peppers, cooking it for 1 to 2 minutes.
Add the tomato sauce, coconut sugar, maple syrup and mustard. Mix to combine. Add the lentils, bring to a high simmer and cook for 12 to 15 minutes, until the sauce has thickened. Stir in lime juice.
Pile the lentil mixture on the buns. Enjoy!