Follow steps 1 through 4 of Canning Instructions, using seven pint-size jars.
Coarsely chop tomatoes; you should have 3 quarts, including juices. Stem, seed, and coarsely chop bell peppers; you should have 1 1/2 quarts. Peel and coarsely chop onions; you should have 1 1/2 quarts. Stem and mince jalapeños; you should have 3/4 cup.
In an 8- to 10-quart pan, combine tomatoes, bell peppers, onions, jalapeños, vinegar, lemon juice, garlic, salt, chile flakes, pepper, and cumin. Measure volume. Bring to a boil over high heat, stirring occasionally. Reduce heat to medium-high and stir often for 1 hour. Reduce heat to medium and stir often until thick and reduced by half, about 1 hour more.
Follow steps 5 through 11 of Canning Instructions, leaving 1/2 inch of headspace in each jar and processing jars for 15 minutes (see notes).
Note: Nutritional analysis is per tablespoon.